wifi: iwlwifi: mei: clarify iwl_mei_pldr_req() docs

wifi: iwlwifi: mei: clarify iwl_mei_pldr_req() docs

This isn't related to whether or not "fw can be loaded",
but rather requesting that ME go into a state where doing
a product reset is safe. This is related to FW load only
in the specific case of where it's used today in iwlmvm,
notably when it's known that the firmware itself will (or
at least may) do a product reset during load.

Clarify the documentation.

I was tempted to rename things too, but on the ME side it
really is also called PLDR (which is a Windows term and
may not even match the complete behaviour since doing a
full product reset from the driver also requires calling
an ACPI method first.) So keep the name aligned with ME.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20240618194245.ca2c55121a04.I889cd47210367ca9110411472ee696b796a37ab5@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>