rockchip: rk3328: migrate to use common spl board file

rk3328 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 3497920..05d207d 100644
--- a/arch/arm/mach-rockchip/Kconfig
+++ b/arch/arm/mach-rockchip/Kconfig
@@ -105,6 +105,7 @@
 	select ARM64
 	select SUPPORT_SPL
 	select SPL
+	imply SPL_ROCKCHIP_COMMON_BOARD
 	imply SPL_SERIAL_SUPPORT
 	imply SPL_SEPARATE_BSS
 	select ENABLE_ARM_SOC_BOOT0_HOOK