pinctrl: mediatek: fix check on EINT_NA comparison

Currently, the check on desc->eint.eint_n == EINT_NA is always false
because this is comparing a u16 to -1 which can never be true.  Fix
this by casting EINT_NA to u16.

Detected by CoverityScan, CID#1473610 ("Operands don't affect result")

Fixes: fb5fa8dc ("pinctrl: mediatek: extend struct mtk_pin_desc to pinctrl-mtk-common-v2.c")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/mediatek/pinctrl-moore.c

@@ -476,7 +476,7 @@ static int mtk_gpio_to_irq(struct gpio_chip *chip, unsigned int offset)
 
 	desc = (const struct mtk_pin_desc *)&hw->soc->pins[offset];
 
-	if (desc->eint.eint_n == EINT_NA)
+	if (desc->eint.eint_n == (u16)EINT_NA)
 		return -ENOTSUPP;
 
 	return mtk_eint_find_irq(hw->eint, desc->eint.eint_n);
@@ -493,7 +493,7 @@ static int mtk_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
 
 	if (!hw->eint ||
 	    pinconf_to_config_param(config) != PIN_CONFIG_INPUT_DEBOUNCE ||
-	    desc->eint.eint_n == EINT_NA)
+	    desc->eint.eint_n == (u16)EINT_NA)
 		return -ENOTSUPP;
 
 	debounce = pinconf_to_config_argument(config);