iwlwifi: acpi: support reading and storing WGDS revision 2

Revisions 0 and 1 are identical, so we were already supporting that.
But revision 2 has a different size, so we have to try to read them
separately.

Add support for this new revision.

Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210805141826.78e441b16f9c.I2d79492f05624ddd02c533c673811a36eaf8a396@changeid


Signed-off-by: Luca Coelho <luciano.coelho@intel.com>