Merge branch 'fixed_phy_register-return-value'

Ruan Jinjie says:

====================
net: Return PTR_ERR() for fixed_phy_register()

fixed_phy_register() returns not only -EIO or -ENODEV, but also
-EPROBE_DEFER, -EINVAL and -EBUSY. The Best practice is to return these
error codes with PTR_ERR().
====================

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