iwlwifi: mvm: honour firmware SMPS requests

iwlwifi: mvm: honour firmware SMPS requests

The firmware can now request SMPS (due to thermal conditions), add
some code to honour such requests and bubble them up through the
stack, subject to our other SMPS constraints, e.g. from Bluetooth.

Then, if the firmware requests SMPS, then we know that it supports
a small extension to the PHY configuration API where a chain mask
of 0 means "use 1 but pick which one yourself", so in this case we
use that extension.

During firmware restart, we stay in the previous state, and the FW
will send us a notification at startup (only) if the temperature is
below the lower or above the high threshold, to sync the state.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210617100544.85656b7684b9.I7a661a0758d070a750d3a91874d1a0f5fab9febc@changeid
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>