arm64: exynos: Enable generic power domain support

Generic power domains are needed to enable support for Exynos power
domains.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm64/Kconfig.platforms

@@ -68,6 +68,7 @@ config ARCH_EXYNOS
 	select HAVE_S3C_RTC if RTC_CLASS
 	select PINCTRL
 	select PINCTRL_EXYNOS
+	select PM_GENERIC_DOMAINS if PM
 	select SOC_SAMSUNG
 	help
 	  This enables support for ARMv8 based Samsung Exynos SoC family.