i40e: add required include

On some architectures, this header must be explicitly included.

Change-ID: I4bc2eb0531956a7b676489f79d347d55cfe12421
Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Tested-by: Kavindya Deegala <kavindya.s.deegala@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

diff --cc drivers/net/ethernet/intel/i40e/i40e.h
Simple merge

diff --cc drivers/net/ethernet/intel/i40e/i40e_txrx.c
Simple merge