mfd: sm501: Add check for platform_driver_register()

As platform_driver_register() can return error numbers,
it should be better to check platform_driver_register()
and deal with the exception.

Fixes: b6d6454f ("[PATCH] mfd: SM501 core driver")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20220913091112.1739138-1-jiasheng@iscas.ac.cn

drivers/mfd/sm501.c

@@ -1720,7 +1720,12 @@ static struct platform_driver sm501_plat_driver = {
 
 static int __init sm501_base_init(void)
 {
-	platform_driver_register(&sm501_plat_driver);
+	int ret;
+
+	ret = platform_driver_register(&sm501_plat_driver);
+	if (ret < 0)
+		return ret;
+
 	return pci_register_driver(&sm501_pci_driver);
 }