ath79: fix default config for devices with eth0/eth1 swapped

ath79: fix default config for devices with eth0/eth1 swapped

also fix the following problems in this commit:
glinet,gl-ar150: This router uses an uncommon order of setting up gmacs
                 in ar71xx. gmac0 is preferred to be wan port because of
                 the additional link status info available. So this
                 router will have eth0/eth1 swapped comparing to ar71xx.
tplink,tl-wr710n-v1: same as gl-ar150
embeddedwireless,dorin: eth0 is used as switch port, which was incorrect.
                        It's correct now, so keep this one untouched.
tplink,tl-wr842n-v1: we don't swap PHYs on ar7241 so the original port order
                     is incorrect.
reorder archer-a7-v5 entry.

Signed-off-by: Chuanhong Guo <gch981213@gmail.com>