ACPI: scan: Simplify acpi_table_events_fn()
Notice that the table field of struct acpi_table_events_work is never
read and its event field is always equal to ACPI_TABLE_EVENT_LOAD, so
both of them are redundant.
Accordingly, drop struct acpi_table_events_work and use struct
work_struct directly instead of it, simplify acpi_scan_table_handler()
and rename it to acpi_scan_table_notify().
Moreover, make acpi_bus_table_handler() check the event code against
ACPI_TABLE_EVENT_LOAD before calling acpi_scan_table_notify(), so it
is not necessary to do that check in the latter.
No intentional functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>