Added Self-protected action category (including MPM).

Added Self-protected action category (including MPM).

* Added new action category IEEE80211_ACTION_CAT_SELF_PROT which is used by 11s
for Mesh Peering Management;
* Updated Self protected enum Action codes to start from 1 instead of 0
according to the standard spec;
* Removed old and wrong action categories IEEE80211_ACTION_CAT_MESHPEERING;
* Modified ieee80211_mesh.c and ieee80211_action.c to use the new action
category code;
* Added earlier verification code in ieee80211_input;

Approved by: adrian