nfp: reorganize pkt_off variable

Rename pkt_off variable to dma_off, it should hold data offset
counting from beginning of DMA mapping.  Compute the value only
in XDP context.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 file changed