scsi: target/iscsi: Reduce number of __iscsit_free_cmd() callers

scsi: target/iscsi: Reduce number of __iscsit_free_cmd() callers

Instead of calling __iscsit_free_cmd() from inside iscsit_aborted_task() if
a command has been aborted and from inside iscsit_free_cmd() if a command
has not been aborted, call __iscsit_free_cmd() from inside
lio_release_cmd(). The latter function is namely called for all commands
once the reference count has dropped to zero.

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Mike Christie <mchristi@redhat.com>
Cc: Varun Prakash <varun@chelsio.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>