Merge branch 'get_phy_device-retval'

Sergei Shtylyov says:

====================
Don't return NULL from get_phy_device() anymore

   Here's the set of 5 patches against DaveM's 'net-next.git' repo. The first
patch makes get_phy_device() return only error values on error, the rest of
the patches clean up the callers of that function...
====================

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