Revert "gpio: revert get() to non-errorprogating behaviour"

This reverts commit 45ad7db9.

We have fixed all the drivers that were returning ambious values
not clamped to [0,1] or an error code, so return the error
propagating behaviour of the API.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpiolib.c

@@ -1303,13 +1303,7 @@ static int _gpiod_get_raw_value(const struct gpio_desc *desc)
 	chip = desc->chip;
 	offset = gpio_chip_hwgpio(desc);
 	value = chip->get ? chip->get(chip, offset) : -EIO;
-	/*
-	 * FIXME: fix all drivers to clamp to [0,1] or return negative,
-	 * then change this to:
-	 * value = value < 0 ? value : !!value;
-	 * so we can properly propagate error codes.
-	 */
-	value = !!value;
+	value = value < 0 ? value : !!value;
 	trace_gpio_value(desc_to_gpio(desc), 1, value);
 	return value;
 }