scsi: iscsi target: have iscsit_start_nopin_timer call __iscsit_start_nopin_timer

Just have iscsit_start_nopin_timer grab the lock and call
__iscsit_start_nopin_timer.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>