nommu: Fix up vmalloc_node() symbol export regression.

Commit e1ca778 ("mm: add vzalloc() and vzalloc_node() helpers") ended up
accidentally deleting the vmalloc_node() symbol export, resulting in:

"vmalloc_node" [net/core/pktgen.ko] undefined!
"vmalloc_node" [net/netfilter/x_tables.ko] undefined!

regressions.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/mm/nommu.c b/mm/nommu.c
index 27a9ac5..275608c 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -328,6 +328,7 @@
 {
 	return vmalloc(size);
 }
+EXPORT_SYMBOL(vmalloc_node);
 
 /**
  * vzalloc_node - allocate memory on a specific node with zero fill