iwlwifi: mvm: rs: don't allow TPC when power save is disabled

Currently we were checking only if the driver power_scheme is set
to CAM. TPC shouldn't be enabled also when disabling powersave on the
interface (e.g. iw wlan0 set power_save off)
which may occur even if power_scheme wasn't set to CAM.

Signed-off-by: Eyal Shapira <eyalx.shapira@intel.com>
Reviewed-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>