ixgbe: add new wrapper for X550 support

For the X550 mac type we have to do additional steps around
enabling/disabling Rx.  This patch will add a layer of indirection
around these support functions to enable this.

CC: <kernel-team@fb.com>
Signed-off-by: Don Skidmore <donald.c.skidmore@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

diff --cc drivers/net/ethernet/intel/ixgbe/ixgbe_82598.c
Simple merge

diff --cc drivers/net/ethernet/intel/ixgbe/ixgbe_82599.c
Simple merge

diff --cc drivers/net/ethernet/intel/ixgbe/ixgbe_common.c
Simple merge

diff --cc drivers/net/ethernet/intel/ixgbe/ixgbe_common.h
Simple merge

diff --cc drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
Simple merge

diff --cc drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
Simple merge

diff --cc drivers/net/ethernet/intel/ixgbe/ixgbe_type.h
Simple merge

diff --cc drivers/net/ethernet/intel/ixgbe/ixgbe_x540.c
Simple merge

diff --cc drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c
Simple merge