rtc: s5m: check the return value of s5m8767_rtc_init_reg()

This function can fail if regmap operations fail so check its return
value in probe().

Signed-off-by: Bartosz Golaszewski <[e-mail]>
Reviewed-by: Krzysztof Kozlowski <[e-mail]>
Signed-off-by: Alexandre Belloni <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/rtc/rtc-s5m.c

···
 	platform_set_drvdata(pdev, info);
 
 	ret = s5m8767_rtc_init_reg(info);
+	if (ret)
+		return ret;
 
 	device_init_wakeup(&pdev->dev, 1);