staging: vc04_services: Use __func__

This was found using checkpatch.pl's EMBEDDED_FUNCTION_NAME warning.
It is easier to be consistent and always use __func__ instead of having
to remember to update any hardcoded references to the original name.
Signed-off-by: Genki Sky <sky@genki.is>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c

@@ -618,8 +618,8 @@ static void buffer_to_host_cb(struct vchiq_mmal_instance *instance,
 	struct mmal_msg_context *msg_context;
 	u32 handle;
 
-	pr_debug("buffer_to_host_cb: instance:%p msg:%p msg_len:%d\n",
-		 instance, msg, msg_len);
+	pr_debug("%s: instance:%p msg:%p msg_len:%d\n",
+		 __func__, instance, msg, msg_len);
 
 	if (msg->u.buffer_from_host.drvbuf.magic == MMAL_MAGIC) {
 		handle = msg->u.buffer_from_host.drvbuf.client_context;