rockchip: rk3399: use common TPL board file

Use common tpl.c instead of rk3399-board-tpl.c

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 28bae2e..2f0d741 100644
--- a/arch/arm/mach-rockchip/Kconfig
+++ b/arch/arm/mach-rockchip/Kconfig
@@ -182,6 +182,7 @@
 	imply TPL_RAM
 	imply TPL_CLK
 	imply TPL_TINY_MEMSET
+	imply TPL_ROCKCHIP_COMMON_BOARD
 	help
 	  The Rockchip RK3399 is a ARM-based SoC with a dual-core Cortex-A72
 	  and quad-core Cortex-A53.