ACPICA: GPEs: Do not allow enable for GPEs that have no handler(s).

ACPICA commit 23b5a8542283af28c3a3a4e3f81096d6e2569faa

There is no point in enabling a GPE that has no handler or
GPE method. At worst, it can cause GPE floods.
Rafael Wysocki.

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