mac80211: make b43 N-PHY default for brcm47xx legacy subtarget

mac80211: make b43 N-PHY default for brcm47xx legacy subtarget

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>
SVN-Revision: 45309