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/Makefile b/arch/arm/mach-rockchip/Makefile
index a12b8d4..b831ec6 100644
--- a/arch/arm/mach-rockchip/Makefile
+++ b/arch/arm/mach-rockchip/Makefile
@@ -7,6 +7,7 @@
 # inaccessible/protected memory (and the bootrom-helper assumes that
 # the stack-pointer is valid before switching to the U-Boot stack).
 obj-spl-$(CONFIG_ROCKCHIP_BROM_HELPER) += bootrom.o
+obj-spl-$(CONFIG_SPL_ROCKCHIP_COMMON_BOARD) += spl.o spl-boot-order.o
 obj-tpl-$(CONFIG_ROCKCHIP_BROM_HELPER) += bootrom.o
 obj-tpl-$(CONFIG_TPL_ROCKCHIP_COMMON_BOARD) += tpl.o