rockchip: rk3399: split roc-pc-rk3399 out of evb_rk3399

roc-pc-rk3399 board has one user button & three user LED's. Currently
we don't have any code support for these devices. Since button and LED's are
specific to roc-pc-rk3399 board, split it into its own board file and add code
support here.

Signed-off-by: Suniel Mahesh <sunil@amarulasolutions.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/configs/roc-pc-rk3399_defconfig b/configs/roc-pc-rk3399_defconfig
index 81e94fe..577ba77 100644
--- a/configs/roc-pc-rk3399_defconfig
+++ b/configs/roc-pc-rk3399_defconfig
@@ -3,6 +3,7 @@
 CONFIG_SYS_TEXT_BASE=0x00200000
 CONFIG_ENV_OFFSET=0x3F8000
 CONFIG_ROCKCHIP_RK3399=y
+CONFIG_TARGET_ROC_PC_RK3399=y
 CONFIG_NR_DRAM_BANKS=1
 CONFIG_DEBUG_UART_BASE=0xFF1A0000
 CONFIG_DEBUG_UART_CLOCK=24000000