ACPICA: Remove restriction of 256 maximum GPEs in any GPE block

The FADT can support over 1000 GPEs, so remove any restriction
on the GPE numbers.

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