mips: ath79: add AP121 reference board

This patch add board-level code and base DT for AP121.

Signed-off-by: Wills Wang <wills.wang@live.com>
[updated defconfig, enabled CONFIG_USE_PRIVATE_LIBGCC=y]
Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
10 files changed