rockchip: add common board file for U-Boot proper

Add common board file for Rockchip SoCs to avoid too much
copy-paste work for different SoCs.
This board file in charge for common board_init() and board_late_init()
in U-Boot proper.

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/arch/arm/mach-rockchip/Kconfig b/arch/arm/mach-rockchip/Kconfig
index 81dee9e..4d983f8 100644
--- a/arch/arm/mach-rockchip/Kconfig
+++ b/arch/arm/mach-rockchip/Kconfig
@@ -229,6 +229,13 @@
           SPL will return to the boot rom, which will then load the U-Boot
           binary to keep going on.
 
+config ROCKCHIP_COMMON_BOARD
+	bool "Rockchip common board file"
+	help
+	  Rockchip SoCs have similar boot process, Common board file is mainly
+	  in charge of common process of board_init() and board_late_init() for
+	  U-Boot proper.
+
 config SPL_ROCKCHIP_COMMON_BOARD
 	bool "Rockchip SPL common board file"
 	depends on SPL