pinctrl: mediatek: fix Kconfig build errors for moore core

pinctrl: mediatek: fix Kconfig build errors for moore core

on i386 or x86_64:

Lots of build errors for drivers/pinctrl/mediatek/pinctrl-moore.c when
CONFIG_OF is not enabled (but COMPILE_TEST is).

first this:
WARNING: unmet direct dependencies detected for PINCTRL_MTK_MOORE
  Depends on [n]: PINCTRL [=y] && (ARCH_MEDIATEK || COMPILE_TEST [=y])
  && OF [=n]
  Selected by [y]:
  - PINCTRL_MT7623 [=y] && PINCTRL [=y] &&
  (ARCH_MEDIATEK || COMPILE_TEST [=y]) && (MACH_MT7623 || COMPILE_TEST [=y])

and then:
../drivers/pinctrl/mediatek/pinctrl-moore.c:22:44: error: array type has
   incomplete element type
   static const struct pinconf_generic_params mtk_custom_bindings[] = {
(etc)

Fixes: b5af33df50e9 ("pinctrl: mediatek: improve Kconfig dependencies")
Cc: stable@vger.kernel.org
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Acked-by: Sean Wang <sean.wang@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>