staging: comedi: hwdrv_apci035: remove useless return statement

Checkpatch pointed out a void function with a return statement.  It can be
removed.

Signed-off-by: Chase Southwood <chase.southwood@gmail.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Cc: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/addi-data/hwdrv_apci035.c

@@ -477,6 +477,4 @@ static void apci035_interrupt(int irq, void *d)
 		/*  send signal to the sample */
 		send_sig(SIGIO, devpriv->tsk_Current, 0);
 	}
-
-	return;
 }