rockchip: rk322x: migrate to use common spl board file

rk322x has similar boot flow in SPL with other Rockchip SoCs,
migrate to use common spl board file.

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 66d07f6..1904322 100644
--- a/arch/arm/mach-rockchip/Kconfig
+++ b/arch/arm/mach-rockchip/Kconfig
@@ -59,6 +59,7 @@
 	select TPL_NEEDS_SEPARATE_STACK if TPL
 	select SPL_DRIVERS_MISC_SUPPORT
 	imply SPL_SERIAL_SUPPORT
+	imply SPL_ROCKCHIP_COMMON_BOARD
 	imply TPL_SERIAL_SUPPORT
 	imply TPL_ROCKCHIP_COMMON_BOARD
 	select TPL_LIBCOMMON_SUPPORT