xen: xensyms support

Export Xen symbols to dom0 via /proc/xen/xensyms (similar to
/proc/kallsyms).

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

drivers/xen/xenfs/xenfs.h

@@ -3,5 +3,6 @@
 
 extern const struct file_operations xsd_kva_file_ops;
 extern const struct file_operations xsd_port_file_ops;
+extern const struct file_operations xensyms_ops;
 
 #endif	/* _XENFS_XENBUS_H */