scsi: xen: scsiback: Fix potential memory leak in scsiback_remove()

Memory allocated for struct vscsiblk_info in scsiback_probe() is not
freed in scsiback_remove() leading to potential memory leaks on remove,
as well as in the scsiback_probe() error paths. Fix that by freeing it
in scsiback_remove().

Cc: [e-mail]
Fixes: d9d660f6e562 ("xen-scsiback: Add Xen PV SCSI backend driver")
Signed-off-by: Abdun Nihaal <[e-mail]>
Reviewed-by: Juergen Gross <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Martin K. Petersen <[e-mail]>

drivers/xen/xen-scsiback.c

···
 	gnttab_page_cache_shrink(&info->free_pages, 0);
 
 	dev_set_drvdata(&dev->dev, NULL);
+	kfree(info);
 }
 
 static int scsiback_probe(struct xenbus_device *dev,