maint: avoid useless "if (foo) free(foo)" pattern

My Coccinelle semantic patch finds a few more, because it also fixes up
the equally pointless conditional

    if (foo) {
        free(foo);
        foo = NULL;
    }

Result (feel free to squash it into your patch):
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

hw/char/exynos4210_uart.c

@@ -234,10 +234,8 @@ static int fifo_empty_elements_number(Exynos4210UartFIFO *q)
 
 static void fifo_reset(Exynos4210UartFIFO *q)
 {
-    if (q->data != NULL) {
-        g_free(q->data);
-        q->data = NULL;
-    }
+    g_free(q->data);
+    q->data = NULL;
 
     q->data = (uint8_t *)g_malloc0(q->size);
 

hw/net/rtl8139.c

@@ -3391,10 +3391,8 @@ static void pci_rtl8139_uninit(PCIDevice *dev)
 {
     RTL8139State *s = RTL8139(dev);
 
-    if (s->cplus_txbuffer) {
-        g_free(s->cplus_txbuffer);
-        s->cplus_txbuffer = NULL;
-    }
+    g_free(s->cplus_txbuffer);
+    s->cplus_txbuffer = NULL;
     timer_del(s->timer);
     timer_free(s->timer);
     qemu_del_nic(s->nic);

hw/ppc/spapr_pci.c

@@ -1460,10 +1460,8 @@ static void spapr_pci_pre_save(void *opaque)
     gpointer key, value;
     int i;
 
-    if (sphb->msi_devs) {
-        g_free(sphb->msi_devs);
-        sphb->msi_devs = NULL;
-    }
+    g_free(sphb->msi_devs);
+    sphb->msi_devs = NULL;
     sphb->msi_devs_num = g_hash_table_size(sphb->msi);
     if (!sphb->msi_devs_num) {
         return;
@@ -1490,10 +1488,8 @@ static int spapr_pci_post_load(void *opaque, int version_id)
                          sizeof(sphb->msi_devs[i].value));
         g_hash_table_insert(sphb->msi, key, value);
     }
-    if (sphb->msi_devs) {
-        g_free(sphb->msi_devs);
-        sphb->msi_devs = NULL;
-    }
+    g_free(sphb->msi_devs);
+    sphb->msi_devs = NULL;
     sphb->msi_devs_num = 0;
 
     return 0;

hw/sd/sdhci.c

@@ -1169,10 +1169,8 @@ static void sdhci_uninitfn(SDHCIState *s)
     qemu_free_irq(s->eject_cb);
     qemu_free_irq(s->ro_cb);
 
-    if (s->fifo_buffer) {
-        g_free(s->fifo_buffer);
-        s->fifo_buffer = NULL;
-    }
+    g_free(s->fifo_buffer);
+    s->fifo_buffer = NULL;
 }
 
 const VMStateDescription sdhci_vmstate = {

hw/usb/hcd-ehci-pci.c

@@ -95,10 +95,8 @@ static void usb_ehci_pci_exit(PCIDevice *dev)
 
     usb_ehci_unrealize(s, DEVICE(dev), NULL);
 
-    if (s->irq) {
-        g_free(s->irq);
-        s->irq = NULL;
-    }
+    g_free(s->irq);
+    s->irq = NULL;
 }
 
 static void usb_ehci_pci_reset(DeviceState *dev)

tests/test-hbitmap.c

@@ -139,10 +139,8 @@ static void hbitmap_test_teardown(TestHBitmapData *data,
         hbitmap_free(data->hb);
         data->hb = NULL;
     }
-    if (data->bits) {
-        g_free(data->bits);
-        data->bits = NULL;
-    }
+    g_free(data->bits);
+    data->bits = NULL;
 }
 
 /* Set a range in the HBitmap and in the shadow "simple" bitmap.

translate-all.c

@@ -731,10 +731,8 @@ void tb_free(TranslationBlock *tb)
 
 static inline void invalidate_page_bitmap(PageDesc *p)
 {
-    if (p->code_bitmap) {
-        g_free(p->code_bitmap);
-        p->code_bitmap = NULL;
-    }
+    g_free(p->code_bitmap);
+    p->code_bitmap = NULL;
     p->code_write_count = 0;
 }
 

vl.c

@@ -534,10 +534,8 @@ const char *qemu_get_vm_name(void)
 
 static void res_free(void)
 {
-    if (boot_splash_filedata != NULL) {
-        g_free(boot_splash_filedata);
-        boot_splash_filedata = NULL;
-    }
+    g_free(boot_splash_filedata);
+    boot_splash_filedata = NULL;
 }
 
 static int default_driver_check(void *opaque, QemuOpts *opts, Error **errp)

xen-mapcache.c

@@ -169,10 +169,8 @@ static void xen_remap_bucket(MapCacheEntry *entry,
             exit(-1);
         }
     }
-    if (entry->valid_mapping != NULL) {
-        g_free(entry->valid_mapping);
-        entry->valid_mapping = NULL;
-    }
+    g_free(entry->valid_mapping);
+    entry->valid_mapping = NULL;
 
     for (i = 0; i < nb_pfn; i++) {
         pfns[i] = (address_index << (MCACHE_BUCKET_SHIFT-XC_PAGE_SHIFT)) + i;