LinuxKPI: 802.11 header updates and add/adjust source dependencies.

LinuxKPI: 802.11 header updates and add/adjust source dependencies.

This update is for more/newer versions of drivers:
- add and properly place more structs, enums, defines needed by drivers.
- correct types of struct fields.
- make various function arguments const.
- move REG_RULE() macro to its own file regulatory.h and
  use macros for calculations.
- add linuxkpi_ieee80211_get_channel() implementation.
- change linuxkpi_ieee80211_ifattach() to return int for error checking.

No intended functional changes for iwlwifi.

Sponsored by:	The FreeBSD Foundation (partially)
MFC after:	3 days