Merge branch 'Move-MDIO-drivers-into-their-own-directory'

Andrew Lunn says:

====================
Move MDIO drivers into their own directory

The phy subdirectory is getting cluttered. It has both PHY drivers and
MDIO drivers, plus a stray switch driver. Soon more PCS drivers are
likely to appear.

Move MDIO and PCS drivers into new directories. This requires fixing
up the xgene driver which uses a relative include path.

v2:
Move the subdirs to drivers/net, rather than drivers/net/phy.

v3:
Add subdirectories under include/linux for mdio and pcs

v4:
there->their
include path fix
No new kconfig prompts
====================

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