rockchip: add common spl board file

The common spl board file handles board_init_f() in SPL,
and with board_early_init_f() and arch_cpu_init() callback,
other operateion after board_init_f() should go to board specific
spl_board_init().

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 17f31e8..ac86532 100644
--- a/arch/arm/mach-rockchip/Kconfig
+++ b/arch/arm/mach-rockchip/Kconfig
@@ -227,6 +227,14 @@
           SPL will return to the boot rom, which will then load the U-Boot
           binary to keep going on.
 
+config SPL_ROCKCHIP_COMMON_BOARD
+	bool "Rockchip SPL common board file"
+	depends on SPL
+	help
+	  Rockchip SoCs have similar boot process, SPL is mainly in charge of
+	  load and boot Trust ATF/U-Boot firmware, and DRAM init if there is
+	  no TPL for the board.
+
 config TPL_ROCKCHIP_COMMON_BOARD
 	bool ""
 	depends on TPL