wifi: iwlwifi: small cleanups in PPAG table flows

1. The name of iwl_read_ppag_table is misleading, as this function only
   fills the command structure from the previously read table. Rename it.
2. Don't initialize fwrt::ppag_flags to 0 as the entire fwrt is zeroed
   in the INIT stage anyway.
3. Don't filter out the reserved bits from fwrt::ppag_flags when printing
   it, as it is already done in 'read-from-bios' flow.

Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Reviewed-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://msgid.link/20240131091413.48acf340e817.I810e457b80015c1931d96d3e13c849f0339723c3@changeid


Signed-off-by: Johannes Berg <johannes.berg@intel.com>