cfg80211: Advertise extended capabilities per interface type to userspace

The driver extended capabilities may differ for different
interface types which the userspace needs to know (for
example the fine timing measurement initiator and responder
bits might differ for a station and AP). Add a new nl80211
attribute to provide extended capabilities per interface type
to userspace.

Signed-off-by: Vidyullatha Kanchanapally <vkanchan@qti.qualcomm.com>
Reviewed-by: Jouni Malinen <jouni@qca.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>