qxl: Use g_new() & friends where that makes obvious sense

g_new(T, n) is neater than g_malloc(sizeof(T) * n).  It's also safer,
for two reasons.  One, it catches multiplication overflowing size_t.
Two, it returns T * rather than void *, which lets the compiler catch
more type errors.

This commit only touches allocations with size arguments of the form
sizeof(T).  Same Coccinelle semantic patch as in commit b45c03f5.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NGerd Hoffmann <kraxel@redhat.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

hw/display/qxl.c

@@ -2156,7 +2156,7 @@ static int qxl_post_load(void *opaque, int version)
         qxl_create_guest_primary(d, 1, QXL_SYNC);
 
         /* replay surface-create and cursor-set commands */
-        cmds = g_malloc0(sizeof(QXLCommandExt) * (d->ssd.num_surfaces + 1));
+        cmds = g_new0(QXLCommandExt, d->ssd.num_surfaces + 1);
         for (in = 0, out = 0; in < d->ssd.num_surfaces; in++) {
             if (d->guest_surfaces.cmds[in] == 0) {
                 continue;