qemu: fix implicit fallthrough warning

src/qemu/qemu_domain_address.c:680:13: error: this statement may fall through [-Werror=implicit-fallthrough=]
             switch ((virDomainFSModel) dev->data.fs->model) {
Signed-off-by: NJán Tomko <jtomko@redhat.com>
Fixes: f363af7e

src/qemu/qemu_domain_address.c

@@ -688,6 +688,7 @@ qemuDomainDeviceCalculatePCIConnectFlags(virDomainDeviceDefPtr dev,
             case VIR_DOMAIN_FS_MODEL_LAST:
                 break;
             }
+            break;
 
         case VIR_DOMAIN_FS_DRIVER_TYPE_LOOP:
         case VIR_DOMAIN_FS_DRIVER_TYPE_NBD: