Add support for the Comtrend AR-5315u router
This a BCM6318 based board, 64 MB RAM, 16 MB SPI flash,
with an onboard BCM43217 wifi, 4 ethernet ports and 1
USB host port
Signed-off-by: Daniel Gonzalez Cabanelas <dgcbueu@gmail.com>
[jonas.gorski: refreshed patch]
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>