rtc: pcf2127: fix error code in pcf2127_enable_ts()

This error path accidentally returns success.  Return -EINVAL instead.

Fixes: 420cc9e8 ("rtc: pcf2127: add support for multiple TS functions")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Bruno Thomsen <bruno.thomsen@gmail.com>
Reviewed-by: Hugo Villeneuve <hugo@hugovil.com>
Reviewed-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/55b9c84b-9d21-444f-b91a-cf9316b65833@moroto.mountainSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-pcf2127.c

@@ -1060,7 +1060,7 @@ static int pcf2127_enable_ts(struct device *dev, int ts_id)
 	if (pcf2127->cfg->ts[ts_id].gnd_detect_bit == 0) {
 		dev_err(dev, "%s: tamper detection to GND configuration invalid\n",
 			__func__);
-		return ret;
+		return -EINVAL;
 	}
 
 	/*