igbvf: remove skb_dma_map/unmap call from drivers

This patch removes the skb_dma_map/unmap calls from the igbvf driver due to
the fact that it does not play well with HW IOMMU when combined with
transmitting cloned skbs.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>