igb: Add support for i354 devices

This patch adds base support for new i354 devices.  Loopback test is
unsupported for this release.

Signed-off-by: Carolyn Wyborny <carolyn.wyborny@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/ethernet/intel/igb/igb.h b/drivers/net/ethernet/intel/igb/igb.h
index d47ac2a..c92115e 100644
--- a/drivers/net/ethernet/intel/igb/igb.h
+++ b/drivers/net/ethernet/intel/igb/igb.h
@@ -122,9 +122,9 @@
  *           descriptors until either it has this many to write back, or the
  *           ITR timer expires.
  */
-#define IGB_RX_PTHRESH	8
+#define IGB_RX_PTHRESH	((hw->mac.type == e1000_i354) ? 12 : 8)
 #define IGB_RX_HTHRESH	8
-#define IGB_TX_PTHRESH	8
+#define IGB_TX_PTHRESH	((hw->mac.type == e1000_i354) ? 20 : 8)
 #define IGB_TX_HTHRESH	1
 #define IGB_RX_WTHRESH	((hw->mac.type == e1000_82576 && \
 			  adapter->msix_entries) ? 1 : 4)