ath9k: pass regd structure directly to regulatory functions

All regulatory information is encapsulated by the ath9k_regulatory
struct, so we can now change all the callers to take that directly
instead of struct ath_hw.  This in turn will enable us to move the
regulatory functions to common code also used by ath5k, since both
can use this regulatory struct.

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