staging: media: lirc: Fix unnecessary return warning.

This patch fixes "void function return statements are not generally
useful" checkpatch.pl warning in lirc_sasem.c
Signed-off-by: Gulsah Kose <gulsah.1004@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/media/lirc/lirc_sasem.c

@@ -474,8 +474,6 @@ static void usb_tx_callback(struct urb *urb)
 	/* notify waiters that write has finished */
 	atomic_set(&context->tx.busy, 0);
 	complete(&context->tx.finished);
-
-	return;
 }
 
 /**
@@ -562,7 +560,6 @@ static void ir_close(void *data)
 	}
 
 	mutex_unlock(&context->ctx_lock);
-	return;
 }
 
 /**
@@ -664,7 +661,6 @@ static void usb_rx_callback(struct urb *urb)
 	}
 
 	usb_submit_urb(context->rx_urb, GFP_ATOMIC);
-	return;
 }