MIPS: add board support for AudioCodes MP-252

Signed-off-by: Daniel Golle <dgolle@allnet.de>
tools: fix lantiq_ram_init_uart.awk for VR9

Signed-off-by: Luka Perkov <luka@openwrt.org>
Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>