gnss: sirf: fix error return code in sirf_probe()

Fix to return a negative error code from the error handling
case instead of 0, as done elsewhere in this function.

This avoids a use-after-free in case the driver is later unbound.

Fixes: d2efbbd18b1e ("gnss: add driver for sirfstar-based receivers")
Reported-by: Hulk Robot <[e-mail]>
Signed-off-by: Wei Yongjun <[e-mail]>
[ johan: amend commit message; mention potential use-after-free ]
Cc: stable <[e-mail]> # 4.19
Signed-off-by: Johan Hovold <[e-mail]>

drivers/gnss/sirf.c

···
 
 	data->on_off = devm_gpiod_get_optional(dev, "sirf,onoff",
 			GPIOD_OUT_LOW);
-	if (IS_ERR(data->on_off))
+	if (IS_ERR(data->on_off)) {
+		ret = PTR_ERR(data->on_off);
 		goto err_put_device;
+	}
 
 	if (data->on_off) {
 		data->wakeup = devm_gpiod_get_optional(dev, "sirf,wakeup",
 				GPIOD_IN);
-		if (IS_ERR(data->wakeup))
+		if (IS_ERR(data->wakeup)) {
+			ret = PTR_ERR(data->wakeup);
 			goto err_put_device;
+		}
 
 		ret = regulator_enable(data->vcc);
 		if (ret)