ixgbe: move setting rx_pb_size into get_invariants

Signed-off-by: Jacob Keller <jacob.e.keller@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_x540.c
Simple merge