greybus: gpio: fix truncated debounce times

Fix set_debounce, which silently truncated the time argument to 255us
even though we support 16-bit values.

Also remove the unnecessary explicit cast when verifying the argument.
Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/staging/greybus/gpio.c

@@ -543,9 +543,9 @@ static int gb_gpio_set_debounce(struct gpio_chip *chip, unsigned offset,
 
 	if (offset >= chip->ngpio)
 		return -EINVAL;
-	if (debounce > (unsigned int)U16_MAX)
+	if (debounce > U16_MAX)
 		return -EINVAL;
-	usec = (u8)debounce;
+	usec = (u16)debounce;
 	ret = gb_gpio_set_debounce_operation(gb_gpio_controller, (u8)offset, usec);
 	if (ret)
 		;	/* return ret; */