James Smart said the userspace to consume these events never emerged.  Given
that these get in the way of the following patches remove support for them.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMike Christie <michaelc@cs.wisc.edu>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Acked-by: NJames Smart <james.smart@emulex.com>