p54: more definitions form lmac_longbow.h and pda.h

This patch ports more useful features to p54
  - PDR definitions for the synth chips & regulatory domain.
  - honour IEEE80211_TX_CTL_ASSIGN_SEQ flag, if it's set.
  - adds some lost mutex_lock & mutex_unlock.
  - replace two more "magic values" that sneaked past.

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