scsi: xen-scsifront: remove DISABLE_CLUSTERING

There is no such limitation in the protocol or implementation, so
remove it.

Signed-off-by: Christoph Hellwig <[e-mail]>
Reviewed-by: Juergen Gross <[e-mail]>
Signed-off-by: Martin K. Petersen <[e-mail]>

drivers/scsi/xen-scsifront.c

···
 	.this_id		= -1,
 	.cmd_size		= sizeof(struct vscsifrnt_shadow),
 	.sg_tablesize		= VSCSIIF_SG_TABLESIZE,
-	.use_clustering		= DISABLE_CLUSTERING,
 	.proc_name		= "scsifront",
 };