igb: Lock buffer size at 2K even on systems with larger pages

This change locks us in at 2K buffers even on a system that supports larger
frames.  The reason for this change is to make better use of pages and to
reduce the overall truesize of frames generated by igb.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/ethernet/intel/igb/igb_ethtool.c b/drivers/net/ethernet/intel/igb/igb_ethtool.c
index 96c6df6..375c0da 100644
--- a/drivers/net/ethernet/intel/igb/igb_ethtool.c
+++ b/drivers/net/ethernet/intel/igb/igb_ethtool.c
@@ -1727,7 +1727,7 @@
 		/* sync Rx buffer for CPU read */
 		dma_sync_single_for_cpu(rx_ring->dev,
 					rx_buffer_info->dma,
-					PAGE_SIZE / 2,
+					IGB_RX_BUFSZ,
 					DMA_FROM_DEVICE);
 
 		/* verify contents of skb */
@@ -1737,7 +1737,7 @@
 		/* sync Rx buffer for device write */
 		dma_sync_single_for_device(rx_ring->dev,
 					   rx_buffer_info->dma,
-					   PAGE_SIZE / 2,
+					   IGB_RX_BUFSZ,
 					   DMA_FROM_DEVICE);
 
 		/* unmap buffer on tx side */