[media] lirc: use kfifo_initialized() on lirc_buffer's fifo

We can use kfifo_initialized() to check if the fifo in lirc_buffer is
initialized or not. There's no need to have a dedicated fifo status
variable in lirc_buffer.

[[e-mail]: add the same change to lirc_zilog, to avoid
breaking compilation of staging drivers]
Signed-off-by: Martin Kaiser <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/staging/media/lirc/lirc_zilog.c

···
 		lirc_unregister_driver(ir->l.minor);
 		ir->l.minor = MAX_IRCTL_DEVICES;
 	}
-	if (ir->rbuf.fifo_initialized)
+	if (kfifo_initialized(&ir->rbuf.fifo))
 		lirc_buffer_free(&ir->rbuf);
 	list_del(&ir->list);
 	kfree(ir);

include/media/lirc_dev.h

···
 	/* Using chunks instead of bytes pretends to simplify boundary checking
 	 * And should allow for some performance fine tunning later */
 	struct kfifo fifo;
-	u8 fifo_initialized;
 };
 
 static inline void lirc_buffer_clear(struct lirc_buffer *buf)
 {
 	unsigned long flags;
 
-	if (buf->fifo_initialized) {
+	if (kfifo_initialized(&buf->fifo)) {
 		spin_lock_irqsave(&buf->fifo_lock, flags);
 		kfifo_reset(&buf->fifo);
 		spin_unlock_irqrestore(&buf->fifo_lock, flags);
···
 	buf->chunk_size = chunk_size;
 	buf->size = size;
 	ret = kfifo_alloc(&buf->fifo, size * chunk_size, GFP_KERNEL);
-	if (ret == 0)
-		buf->fifo_initialized = 1;
 
 	return ret;
 }
 
 static inline void lirc_buffer_free(struct lirc_buffer *buf)
 {
-	if (buf->fifo_initialized) {
+	if (kfifo_initialized(&buf->fifo)) {
 		kfifo_free(&buf->fifo);
-		buf->fifo_initialized = 0;
 	} else
 		WARN(1, "calling %s on an uninitialized lirc_buffer\n",
 		     __func__);