Subtarget legacy is supposed to support all ssb SoC except for BCM4705.
There are few BCM4703 devices with 802.11n supprt (WRT160N v1.0, v1.1).
Few BCM4704 devices with 802.11n: ASUS WL-500W, Linksys WRT150N v1.0 &
v1.1, Linksys WRT300N v1.0, Netgear WNDR3300 v1, WNR834B v1 & v2.

It seems we have to enable N-PHY for legacy as well to support above.
Unfortunately it increases root.squashfs size by 48 460 B.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@45309 3c298f89-4303-0410-b956-a3cf2f4a3e73