arm64: add Rockchip architecture entry

The rk3368 is Rockchip's first ARM64 soc, build around 8 Cortex-A53 cores.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Olof Johansson <olof@lixom.net>

arch/arm64/Kconfig.platforms

@@ -40,6 +40,16 @@ config ARCH_QCOM
 	help
 	  This enables support for the ARMv8 based Qualcomm chipsets.
 
+config ARCH_ROCKCHIP
+	bool "Rockchip Platforms"
+	select ARCH_HAS_RESET_CONTROLLER
+	select ARCH_REQUIRE_GPIOLIB
+	select PINCTRL
+	select PINCTRL_ROCKCHIP
+	help
+	  This enables support for the ARMv8 based Rockchip chipsets,
+	  like the RK3368.
+
 config ARCH_SEATTLE
 	bool "AMD Seattle SoC Family"
 	help