iwlwifi: mvm: fix PSM disable during TDLS

Simplify the code and check for TDLS stations just before sending the
MAC_POWER_TABLE command. The previous version of the code still allowed
PM in some multi-interface scenarios even with TDLS connected.

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>