mips: mtmips: add two reference boards for mt7620

The mt7620_rfb board supports integrated 10/100M PHYs plus two external
giga PHYs. It also has 8MB SPI-NOR, mini PCI-e x1 slot, SDHC and USB.

The mt7620_mt7530_rfb boards supports an external MT7530 giga switch and a
16MB SPI-NOR flash.

Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/arch/mips/dts/Makefile b/arch/mips/dts/Makefile
index e82f96d..7c42923 100644
--- a/arch/mips/dts/Makefile
+++ b/arch/mips/dts/Makefile
@@ -14,6 +14,8 @@
 dtb-$(CONFIG_BOARD_COMTREND_VR3032U) += comtrend,vr-3032u.dtb
 dtb-$(CONFIG_BOARD_COMTREND_WAP5813N) += comtrend,wap-5813n.dtb
 dtb-$(CONFIG_BOARD_HUAWEI_HG556A) += huawei,hg556a.dtb
+dtb-$(CONFIG_BOARD_MT7620_RFB) += mediatek,mt7620-rfb.dtb
+dtb-$(CONFIG_BOARD_MT7620_MT7530_RFB) += mediatek,mt7620-mt7530-rfb.dtb
 dtb-$(CONFIG_BOARD_MT7628_RFB) += mediatek,mt7628-rfb.dtb
 dtb-$(CONFIG_BOARD_GARDENA_SMART_GATEWAY_MT7688) += gardena-smart-gateway-mt7688.dtb
 dtb-$(CONFIG_BOARD_LINKIT_SMART_7688) += linkit-smart-7688.dtb