ACPICA commit a4849944e80f97970e99843f4975850753584a4e

This change adds PCC operation region support in the AML interpreter
and a default handler for acpiexec. According to the specification,
the PCC operation region performs a transaction when the COMD field
is written. This allows ASL to write data to other fields before
sending the data.

In order to accommodate this protocol, a temorary buffer is added
to the regionfield object to accumulate writes. If any offset that
spans COMD is written, the temporary buffer is sent to the PCC
operation region handler to be processed.

This change also renames the PCC keyword to platform_comm_channel.

Link: https://github.com/acpica/acpica/commit/a4849944Reviewed-by: Kyle Pelton <kyle.d.pelton@intel.com>
Signed-off-by: Erik Schmauss <erik.schmauss@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>