vhost-scsi: don't open-code kvfree

Now that we have kvfree, use it in vhost-scsi instead of
the open-coded version.

Cc: Nicholas Bellinger <[e-mail]>
Signed-off-by: Michael S. Tsirkin <[e-mail]>

drivers/vhost/scsi.c

···
 	return 0;
 }
 
-static void vhost_scsi_free(struct vhost_scsi *vs)
-{
-	if (is_vmalloc_addr(vs))
-		vfree(vs);
-	else
-		kfree(vs);
-}
-
 static int vhost_scsi_open(struct inode *inode, struct file *f)
 {
 	struct vhost_scsi *vs;
···
 	return 0;
 
 err_vqs:
-	vhost_scsi_free(vs);
+	kvfree(vs);
 err_vs:
 	return r;
 }
···
 	/* Jobs can re-queue themselves in evt kick handler. Do extra flush. */
 	vhost_scsi_flush(vs);
 	kfree(vs->dev.vqs);
-	vhost_scsi_free(vs);
+	kvfree(vs);
 	return 0;
 }