Input: gpio-keys - convert to dev_err_probe()

Use the dev_err_probe() helper, instead of open-coding the same
operation.

While at it, invert the error checking logic to simplify code flow.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/d225a837c50e2b19a41555a8f7ce0f94b1689aa4.1689600353.git.geert+renesas@glider.beSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/keyboard/gpio_keys.c

@@ -523,18 +523,15 @@ static int gpio_keys_setup_key(struct platform_device *pdev,
 						     NULL, GPIOD_IN, desc);
 		if (IS_ERR(bdata->gpiod)) {
 			error = PTR_ERR(bdata->gpiod);
-			if (error == -ENOENT) {
-				/*
-				 * GPIO is optional, we may be dealing with
-				 * purely interrupt-driven setup.
-				 */
-				bdata->gpiod = NULL;
-			} else {
-				if (error != -EPROBE_DEFER)
-					dev_err(dev, "failed to get gpio: %d\n",
-						error);
-				return error;
-			}
+			if (error != -ENOENT)
+				return dev_err_probe(dev, error,
+						     "failed to get gpio\n");
+
+			/*
+			 * GPIO is optional, we may be dealing with
+			 * purely interrupt-driven setup.
+			 */
+			bdata->gpiod = NULL;
 		}
 	} else if (gpio_is_valid(button->gpio)) {
 		/*