scsi: scsi_debug: Remove dead code

The ramdisk rwlocks are not used anymore.

Fixes: 87c715dc ("scsi: scsi_debug: Add per_host_store option")
Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
Link: https://lore.kernel.org/r/20230628150638.53218-1-mlombard@redhat.com


Reviewed-by: Laurence Oberman <loberman@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>