p54: Move mac80211 glue code

Copy the mac80211 glue code from p54common.c into a new file main.c

Signed-off-by: Christian Lamparter <chunkeey@web.de>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>