Merge branch 'vlan-prepare-for-removal-of-VLAN_TAG_PRESENT'

Michał Mirosław says:

====================
net/vlan: prepare for removal of VLAN_TAG_PRESENT

This is a preparatory patchset before removing the use of VLAN_TAG_PRESENT
bit in skb->vlan_tci as indication of VLAN offload. This set includes
only cleanups that allow abstracting of code testing VLAN tag presence
in drivers and networking code.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>