iwlwifi: mvm: remove some unused defines from RX API

Remove some unused values from the RX API; these were used
with older firmware API that didn't have the RX energy API,
support for which was removed a long time ago.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>