iwlwifi: mvm: disallow new TDLS stations when appropriate

HW/FW constraints dictate that TDLS should only be used when a single
phy ctx is active. We also support at most 4 TDLS peers. We don't
support TDLS on a P2P vif.

Unify and move a phy-ctx counting implementation from the power-mgmt code
in order to simplify implementation.

Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
diff --git a/drivers/net/wireless/iwlwifi/mvm/fw-api.h b/drivers/net/wireless/iwlwifi/mvm/fw-api.h
index 99329ed..b8e4e78 100644
--- a/drivers/net/wireless/iwlwifi/mvm/fw-api.h
+++ b/drivers/net/wireless/iwlwifi/mvm/fw-api.h
@@ -86,6 +86,8 @@
 
 #define IWL_MVM_STATION_COUNT	16
 
+#define IWL_MVM_TDLS_STA_COUNT	4
+
 /* commands */
 enum {
 	MVM_ALIVE = 0x1,