cfg80211: add flags to define country IE processing rules

802.11 cards may have different country IE parsing behavioural
preferences and vendors may want to support these. These preferences
were managed by the REGULATORY_CUSTOM_REG and the REGULATORY_STRICT_REG
flags and their combination. Instead of using this existing notation,
split out the country IE behavioural preferences as a new flag. This
will allow us to add more customizations easily and make the code more
maintainable.

Cc: Mihir Shete <smihir@qti.qualcomm.com>
Cc: Henri Bahini <hbahini@qca.qualcomm.com>
Cc: Tushnim Bhattacharyya <tushnimb@qca.qualcomm.com>
Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>
[fix up conflicts]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>