hwmon: (it87) Check the it87_lock() return value

Return early in it87_resume() if it87_lock() fails instead of ignoring the
return value of that function. This patch suppresses a Clang thread-safety
warning.

Cc: Frank Crawford <[e-mail]>
Cc: Guenter Roeck <[e-mail]>
Cc: Jean Delvare <[e-mail]>
Cc: [e-mail]
Fixes: 376e1a937b30 ("hwmon: (it87) Add calls to smbus_enable/smbus_disable as required")
Signed-off-by: Bart Van Assche <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
[groeck: Declare 'ret' at the beginning of it87_resume()]
Signed-off-by: Guenter Roeck <[e-mail]>

drivers/hwmon/it87.c

···
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct it87_data *data = dev_get_drvdata(dev);
+	int err;
 
 	it87_resume_sio(pdev);
 
-	it87_lock(data);
+	err = it87_lock(data);
+	if (err)
+		return err;
 
 	it87_check_pwm(dev);
 	it87_check_limit_regs(data);