pinctrl: aspeed: Wrap -Woverride-init with cc-option

Clang does not support this option:

warning: unknown warning option '-Woverride-init'; did you mean
'-Woverride-module'? [-Wunknown-warning-option]
1 warning generated.
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Andrew Jeffery <andrew@aj.id.au>
Acked-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/aspeed/Makefile

 # Aspeed pinctrl support
 
-ccflags-y += -Woverride-init
+ccflags-y += $(call cc-option,-Woverride-init)
 obj-$(CONFIG_PINCTRL_ASPEED)	+= pinctrl-aspeed.o
 obj-$(CONFIG_PINCTRL_ASPEED_G4)	+= pinctrl-aspeed-g4.o
 obj-$(CONFIG_PINCTRL_ASPEED_G5)	+= pinctrl-aspeed-g5.o