greybus: gb-vibrator: remove useless if in timeout_store()

val is an unsigned long so there is no point in checking if it is less
than zero.
Signed-off-by: Bill Pemberton <wfp5p@worldbroken.com>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/staging/greybus/gb-vibrator.c

@@ -100,8 +100,6 @@ static ssize_t timeout_store(struct device *dev, struct device_attribute *attr,
 		return retval;
 	}
 
-	if (val < 0)
-		return -EINVAL;
 	if (val)
 		retval = turn_on(vib, (u16)val);
 	else