iwlwifi: mvm: use FW thermal monitoring regardless of CONFIG_THERMAL

It doesn't make sense to use the FW thermal monitoring only if we
have CONFIG_THERMAL, because then we use the default thresholds
etc. which may be different from what the firmware implements, as
we don't maintain them in the driver now. Only the CTDP code needs
to actually be under CONFIG_THERMAL.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>