Use the mii_bus callbacks to address the entire clause 22/45 address
space. Enables userspace to poke switch registers instead of a single
PHY address.
The ixgbe firmware may be polling PHYs in a way that is not protected by
the mii_bus lock. This isn't new behavior, but as Andrew Lunn pointed
out there are more addresses available for conflicts.
Signed-off-by: Stephen Douthit <stephend@silicom-usa.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Tested-by: Andrew Bowers <andrewx.bowers@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>