lpfc: remove queue_depth events

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: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: James Smart <james.smart@emulex.com>