Input: omap4-keypad - fix handling of platform_get_irq() error

platform_get_irq() returns -ERRNO on error.  In such case comparison
to 0 would pass the check.

Fixes: f3a1ba60 ("Input: omap4-keypad - use platform device helpers")
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20200828145744.3636-2-krzk@kernel.orgSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/keyboard/omap4-keypad.c

@@ -240,10 +240,8 @@ static int omap4_keypad_probe(struct platform_device *pdev)
 	}
 
 	irq = platform_get_irq(pdev, 0);
-	if (!irq) {
-		dev_err(&pdev->dev, "no keyboard irq assigned\n");
-		return -EINVAL;
-	}
+	if (irq < 0)
+		return irq;
 
 	keypad_data = kzalloc(sizeof(struct omap4_keypad), GFP_KERNEL);
 	if (!keypad_data) {