ACPICA: Events: Deploys acpi_ev_find_region_handler()

ACPICA commit b916a0a0ae9e81db1a85523c63ec6aa32d5c70c8

There are code fragments that can be substituted by
acpi_ev_find_region_handler().

This patch cleans up these code fragments. Lv Zheng.

Link: https://github.com/acpica/acpica/commit/b916a0a0


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