x86 platform drivers: hp-wmi fix buffer size depending on ACPI version

x86 platform drivers: hp-wmi fix buffer size depending on ACPI version

Depending on ACPI version (1.0 -> 32 bit) an integer could be
32 or 64 bit long. _WED internal concatenates two integers and
the return value will be 8 byte (2* 32 bit) or 16 byte (2* 64 bit)
long, depending on the ACPI version.

Also the data send with the WMI event is defined to be splitted into:
  - Event ID -> 4 bytes
  - Event Data -> 4 bytes

This gets messed up with new ACPI versions.
But it's a HP BIOS bug that may get fixed in the future
-> Support both, 16 and 8 byte _WED buffers.

Also the wrong assumption that from the event data sent, only the
first byte is relevant got cleaned up that it fits event_id/event_data
as described above.

Signed-off-by: Thomas Renninger <trenn@suse.de>
CC: robert.moore@intel.com
Signed-off-by: Matthew Garrett <mjg@redhat.com>
CC: platform-driver-x86@vger.kernel.org
CC: linux-acpi@vger.kernel.org