[PATCH 0/2 gnumach] ACPI v2.0 support

[Damien Zammit]

This enables gnumach to additionally parse the XSDT table
if the version of ACPI is detected to be greater than 1.

TESTED: Should not break existing ACPI v1.0 support.

Almost boots on HP T620 but crashes further downstream
of ACPI table detection (to be fixed in follow up patches).