HID: alps: Check errors returned by 't4_read_write_register()'

If only the first 't4_read_write_register()' call fails, the error code
will be overwritten and lost.
Directly report the error instead.

While at it, log some errors if 't4_read_write_register()' fails, as done
in the rest of the driver.
Signed-off-by: NChristophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

drivers/hid/hid-alps.c

@@ -460,17 +460,35 @@ static int __maybe_unused alps_post_reset(struct hid_device *hdev)
 	case T4:
 		ret = t4_read_write_register(hdev, T4_PRM_FEED_CONFIG_1,
 			NULL, T4_I2C_ABS, false);
+		if (ret < 0) {
+			dev_err(&hdev->dev, "failed T4_PRM_FEED_CONFIG_1 (%d)\n",
+				ret);
+			goto exit;
+		}
+
 		ret = t4_read_write_register(hdev, T4_PRM_FEED_CONFIG_4,
 			NULL, T4_FEEDCFG4_ADVANCED_ABS_ENABLE, false);
+		if (ret < 0) {
+			dev_err(&hdev->dev, "failed T4_PRM_FEED_CONFIG_4 (%d)\n",
+				ret);
+			goto exit;
+		}
 		break;
 	case U1:
 		ret = u1_read_write_register(hdev,
 			ADDRESS_U1_DEV_CTRL_1, NULL,
 			U1_TP_ABS_MODE | U1_SP_ABS_MODE, false);
+		if (ret < 0) {
+			dev_err(&hdev->dev, "failed to change TP mode (%d)\n",
+				ret);
+			goto exit;
+		}
 		break;
 	default:
 		break;
 	}
+
+exit:
 	return ret;
 }