pinctrl: mediatek: convert to arch_initcall

Move pinctrl initialization earlier in boot so that real devices can find
their pctldev without probe deferring.

Note: We don't change mt6397 probe order in this patch, since MT6397 is mfd
PMIC, which depends on pwrap on main AP to work. Since pmic-wrap itself
is module_platform_driver, we keep it as module_init.  A later patch
will convert both pmic-wrap, and all functions of the MT6397 mfd to
arch_initcall.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/pinctrl/mediatek/pinctrl-mt8135.c b/drivers/pinctrl/mediatek/pinctrl-mt8135.c
index 404f117..1c153b8 100644
--- a/drivers/pinctrl/mediatek/pinctrl-mt8135.c
+++ b/drivers/pinctrl/mediatek/pinctrl-mt8135.c
@@ -366,7 +366,7 @@
 	return platform_driver_register(&mtk_pinctrl_driver);
 }
 
-module_init(mtk_pinctrl_init);
+arch_initcall(mtk_pinctrl_init);
 
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("MediaTek Pinctrl Driver");