iwlwifi: mvm: iterate active stations when updating statistics

Instead of enumerating all possible stations iterate only active ones.

Signed-off-by: Mordechay Goodstein <mordechay.goodstein@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20201209231352.c049de5611b4.Ic35b8d1a328903195ec7cb887a9cb198b7d8f856@changeid


Signed-off-by: Luca Coelho <luciano.coelho@intel.com>