iwlwifi: mvm: add support for non EDCA based measurements

Add support for requesting trigger-based / non trigger-based
measurements.

Change-Id: Ib4d0c471da9c50d9981541a7f5926db384a0f7ce
Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>