ixgbe: Move PHY ops initialization to centralize bus accesses

When PHY operations are determined, the PHY must be identified.  This
identification causes bus access, and should be contained within its own
routines.  This also helps the 82599 PHY init paths for both SFP+ and
KX/KX4 devices to be easier to maintain.

Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>