ACPICA: Add struct header support for _FDE, _GRT, _GTM, and _SRT names.

Added structs for the buffers related to these predefined names,
in acbuffer.h

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>