iwlwifi: acpi: move ppag code from mvm to fw/acpi

Move the ppag code to fw/acpi to keep consistency
with the other ACPI handling we do.

Signed-off-by: Matt Chen <matt.chen@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20220304131517.7f250088b443.I61e64c2758ad178da729ce00428287cc94430eed@changeid
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>