[POWERPC] Export new __io{re,un}map_at() symbols

Export new __io{re,un}map_at() symbols so modules can use them.
Signed-off-by: NOlof Johansson <olof@lixom.net>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

arch/powerpc/mm/pgtable_64.c

@@ -228,5 +228,7 @@ void iounmap(volatile void __iomem *token)
 EXPORT_SYMBOL(ioremap);
 EXPORT_SYMBOL(ioremap_flags);
 EXPORT_SYMBOL(__ioremap);
+EXPORT_SYMBOL(__ioremap_at);
 EXPORT_SYMBOL(iounmap);
 EXPORT_SYMBOL(__iounmap);
+EXPORT_SYMBOL(__iounmap_at);