scsi: mpi3mr: Fix a double free

Fix a double free, scsi_tgt_priv_data will be freed in
mpi3mr_target_destroy() so remove the kfree() from mpi3mr_target_alloc().
I've also removed few unneeded initialisations.

Link: https://lore.kernel.org/r/20210608145712.16386-1-thenzl@redhat.com


Acked-by: Kashyap Desai <kashyap.desai@broadcom.com>
Signed-off-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>