wifi: iwlwifi: trans: remove hw_wfpm_id

We only need to have this during init in PCIe, so can
just re-read the value. Do that and don't store it.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20250503224232.4dfa2ae2a844.I46466f2523d8760e93228cd9a93c112d371e002d@changeid