rockchip: Add basic support for firefly-rk3288

The Firefly RK3288 is a suitable target board for initial mainline Rockchip
support. It includes a good set of peripherals, a recent SoC and it is
readily available.

This adds only some basic files required to allow the baord to display a
serial message in SPL and hang.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/board/firefly/firefly-rk3288/MAINTAINERS b/board/firefly/firefly-rk3288/MAINTAINERS
new file mode 100644
index 0000000..42db0bd
--- /dev/null
+++ b/board/firefly/firefly-rk3288/MAINTAINERS
@@ -0,0 +1,6 @@
+FIREFLY
+M:	Simon Glass <sjg@chromium.org>
+S:	Maintained
+F:	board/firefly/firefly-rk3288
+F:	include/configs/firefly-rk3288.h
+F:	configs/firefly-rk3288_defconfig