MIPS: ralink: add support for MT7620n

This is the small version of MT7620a.

Signed-off-by: John Crispin <blogic@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/8030/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2 files changed