ACPICA: Headers: Minor update for SPCR ACPI table

ACPICA commit f3caa7f2e63be31f7fb8dbccabffbb70c29c3021

Update version number and date of specification document.
Point to DBG2 table for some constants.

Link: https://github.com/acpica/acpica/commit/f3caa7f2


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>