staging: dgnc: Remove unnecessary 'return' statement

This commit fixes the checkpath warning 'void function return
statements are not generally useful' caused by the 'return' at the end
of 'void' function.

Signed-off-by: Konrad Zapalowicz <bergo.torino@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/dgnc/dgnc_cls.c

@@ -1138,8 +1138,6 @@ static void cls_copy_data_from_queue_to_uart(struct channel_t *ch)
 		ch->ch_flags &= ~(CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
 
 	DGNC_UNLOCK(ch->ch_lock, lock_flags);
-
-	return;
 }