MIPS: add board support for Arcadyan ARV752DPW22

Signed-off-by: Oliver Muth <dr.o.muth@gmx.de>
Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
MIPS: add board support for Arcadyan ARV7510

Signed-off-by: Matti Laakso <malaakso@elisanet.fi>
Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Makefile: prepare u-boot-lantiq-v2013.10-openwrt4

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>