wifi: iwlwifi: rename iwl_finish_nic_init

wifi: iwlwifi: rename iwl_finish_nic_init

The function is called so because for older devices it sets a bit called
"init_done". But for the latest devices it sets a different bit,
"mac_init". Since this name is not clear anyway, rename it such that it
indicates the logic of the newer devices.
Also add the 'trans' prefix so iw will be clear from the name that this
is a transport API.

Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20250909061931.a1de688e574b.Ibd41b0c8f7fbae77026e76dbbc085df3eecec538@changeid