wifi: iwlwifi: nvm-parse: advertise common packet padding

We should - at least for now - advertise common nominal packet
padding of 16µs instead of the more specific PPE thresholds.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Gregory Greenman <gregory.greenman@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://msgid.link/20240123200528.4312e176dfdc.Ide75980ff57257a31e86e6ac5948a8f97aaab577@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>