ath: move more setup code into ath_regd_init

Setup the wiphy regulatory parameters when first initializing the
Atheros regulatory module.  We can remove five exported symbols this
way and simplify the driver code for both ath5k and ath9k.

Signed-off-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>