scsi: target: srp, vscsi, sbp, qla: use target_remove_session

This converts the drivers that called transport_deregister_session_configfs
and then immediately called transport_deregister_session to use
target_remove_session.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Chris Boot <bootc@bootc.net>
Cc: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Cc: Michael Cyr <mikecyr@linux.vnet.ibm.com>
Cc: <qla2xxx-upstream@qlogic.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>