Symbol rtl8366_enable_vlan and rtl8366_reset_vlan are also present in
the DSA driver upstream and conflicts as they are EXPORTED.
Rename them to rtl8366_smi_enable_vlan and rtl8366_smi_reset_vlan to fix
the conflict. While at it also make them static and drop the
EXPORT_SYMBOL_GPL as they are not actually used by any other driver and
exporting them is useless.
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>