Allows explicity enabling of events

Previously, events were always reported as enabled, but actually only
implicitly enabled when updating the buffer scan mode
Signed-off-by: NPeter Meerwald <pmeerw@pmeerw.net>
Acked-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>