cfg80211: Allow for strict regulatory settings

This allows drivers to request strict regulatory settings to
be applied to its devices. This is desirable for devices where
proper calibration and compliance can only be gauranteed for
for the device's programmed regulatory domain. Regulatory
domain settings will be ignored until the device's own
regulatory domain is properly configured. If no regulatory
domain is received only the world regulatory domain will be
applied -- if OLD_REG (default to "US") is not enabled. If
OLD_REG behaviour is not acceptable to drivers they must
update their wiphy with a custom reuglatory prior to wiphy
registration.

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