rockchip: board: evb-rk3128: add empty Makefile

Even if the board-specific directory Makefile doesn't have any
targets, it still needs to exist.

This adds a minimal Makefile for the board/rockchip/evb_rk3128
directory and a evk-rk3128.c (as built-in.o needs to be built
for every directory that a Makefile gets run for).

Fixes: c7a6866 ("rockchip: rk3128: add evb-rk3128 support")
Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>

board/rockchip/evb_rk3128/Makefile

@@ -0,0 +1,5 @@
+#
+# SPDX-License-Identifier:     GPL-2.0+
+#
+
+obj-y	+= evk-rk3128.o