ehci: fix reset

Check for the reset bit first when processing USBCMD register writes.
Also break out of the switch, there is no need to check the other bits.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

hw/usb/hcd-ehci.c

@@ -1107,6 +1107,12 @@ static void ehci_mem_writel(void *ptr, target_phys_addr_t addr, uint32_t val)
     /* Do any register specific pre-write processing here.  */
     switch(addr) {
     case USBCMD:
+        if (val & USBCMD_HCRESET) {
+            ehci_reset(s);
+            val = s->usbcmd;
+            break;
+        }
+
         if ((val & USBCMD_RUNSTOP) && !(s->usbcmd & USBCMD_RUNSTOP)) {
             qemu_mod_timer(s->frame_timer, qemu_get_clock_ns(vm_clock));
             SET_LAST_RUN_CLOCK(s);
@@ -1121,10 +1127,6 @@ static void ehci_mem_writel(void *ptr, target_phys_addr_t addr, uint32_t val)
             ehci_set_usbsts(s, USBSTS_HALT);
         }
 
-        if (val & USBCMD_HCRESET) {
-            ehci_reset(s);
-            val = s->usbcmd;
-        }
 
         /* not supporting dynamic frame list size at the moment */
         if ((val & USBCMD_FLS) && !(s->usbcmd & USBCMD_FLS)) {