Kconfig: ARCH_HISI: Add PINCTRL to HISI platform

Things won't work if PINCTRL isn't enabled,
so make sure to explicitly set it rather
then betting that we have some other platform
configed in which selects it.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Wei Xu <xuwei5@hisilicon.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Wei Xu <xuwei5@hisilicon.com>