board: rockchip: Add rk3308 evb support

Add support for rk3308 evaluation board.

Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/board/rockchip/evb_rk3308/Kconfig b/board/rockchip/evb_rk3308/Kconfig
new file mode 100644
index 0000000..0074429
--- /dev/null
+++ b/board/rockchip/evb_rk3308/Kconfig
@@ -0,0 +1,15 @@
+if TARGET_EVB_RK3308
+
+config SYS_BOARD
+	default "evb_rk3308"
+
+config SYS_VENDOR
+	default "rockchip"
+
+config SYS_CONFIG_NAME
+	default "evb_rk3308"
+
+config BOARD_SPECIFIC_OPTIONS # dummy
+	def_bool y
+
+endif