arm: MediaTek: add basic support for MT7623 boards

This adds a general board file based on MT7623 SoCs from MediaTek.

As this u-boot is loaded by MTK proprietary preloader, there is no
low level initializtion codes.

Tested-by: Matthias Brugger <matthias.bgg@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/mach-mediatek/mt7623/Makefile b/arch/arm/mach-mediatek/mt7623/Makefile
new file mode 100644
index 0000000..007eb4a
--- /dev/null
+++ b/arch/arm/mach-mediatek/mt7623/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier:	GPL-2.0
+
+obj-y += init.o
+obj-y += lowlevel_init.o