Merge branch 'phy_rgmii'

Florian Fainelli says:

====================
net: phy: phy_interface_is_rgmii helper

As you suggested, here is the helper function to avoid missing some RGMII
interface checks. Had to wait for net to be merged in net-next to avoid
submitting the same patch/commit.

Dan, you might want to rebase your dp83867 submission to use that helper
when you this patchset gets merged into net-next, thanks!
====================

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