firmware: arm_sdei: Remove _sdei_event_unregister()

firmware: arm_sdei: Remove _sdei_event_unregister()

_sdei_event_unregister() is called by sdei_event_unregister() and
sdei_device_freeze(). _sdei_event_unregister() covers the shared
and private events, but sdei_device_freeze() only covers the shared
events. So the logic to cover the private events isn't needed by
sdei_device_freeze().

   sdei_event_unregister        sdei_device_freeze
      _sdei_event_unregister       sdei_unregister_shared
                                     _sdei_event_unregister

This removes _sdei_event_unregister(). Its logic is moved to its
callers accordingly. This shouldn't cause any logical changes.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: James Morse <james.morse@arm.com>
Link: https://lore.kernel.org/r/20200922130423.10173-14-gshan@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>