swiotlb-xen: suppress certain init retries

Only on the 2nd of the paths leading to xen_swiotlb_init()'s "error"
label it is useful to retry the allocation; the first one did already
iterate through all possible order values.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/56477481-87da-4962-9661-5e1b277efde0@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>

drivers/xen/swiotlb-xen.c

@@ -184,7 +184,7 @@ retry:
 		order--;
 	}
 	if (!start)
-		goto error;
+		goto exit;
 	if (order != get_order(bytes)) {
 		pr_warn("Warning: only able to allocate %ld MB for software IO TLB\n",
 			(PAGE_SIZE << order) >> 20);
@@ -214,6 +214,7 @@ error:
 		pr_info("Lowering to %luMB\n", bytes >> 20);
 		goto retry;
 	}
+exit:
 	pr_err("%s (rc:%d)\n", xen_swiotlb_error(m_ret), rc);
 	return rc;
 }