misc: xilinx_flex: Prevent accessing of uninitialised variables

In case of invalid input exit so that uninitialised variables are
not accessed.

Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>

drivers/misc/xilinx_flex_pm.c

@@ -298,7 +298,8 @@ static int xflex_sysfs_cmd(struct device *dev, const char *buf,
 
 	default:
 		dev_err(dev, "Invalid option\n");
-		break;
+		ret = -EINVAL;
+		goto exit_unlock;
 	}
 
 	ret = zynqmp_pm_probe_counter_read(domain, reg, &pm_api_ret[0]);