Input: twl4030_keypad - fix handling of platform_get_irq() error

platform_get_irq() returns -ERRNO on error.  In such case casting to
unsigned and comparing to 0 would pass the check.

Fixes: 7abf38d6d1 ("Input: twl4030-keypad - add device tree support")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20200828145744.3636-3-krzk@kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/keyboard/twl4030_keypad.c

@@ -50,7 +50,7 @@ struct twl4030_keypad {
 	bool		autorepeat;
 	unsigned int	n_rows;
 	unsigned int	n_cols;
-	unsigned int	irq;
+	int		irq;
 
 	struct device *dbg_dev;
 	struct input_dev *input;
@@ -376,10 +376,8 @@ static int twl4030_kp_probe(struct platform_device *pdev)
 	}
 
 	kp->irq = platform_get_irq(pdev, 0);
-	if (!kp->irq) {
-		dev_err(&pdev->dev, "no keyboard irq assigned\n");
-		return -EINVAL;
-	}
+	if (kp->irq < 0)
+		return kp->irq;
 
 	error = matrix_keypad_build_keymap(keymap_data, NULL,
 					   TWL4030_MAX_ROWS,