ACPICA: Add support for LPIT table.

Adds header, disassembler, table compiler, and template support
for the Low Power Idle Table (LPIT).

Note that the disassembler and table compiler are not shipped in
the kernel.

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>