sh_eth: fix TX buffer byte-swapping

sh_eth: fix TX buffer byte-swapping

commit 3e2309937f1e5d538ff13da5fb8de41196927c61 upstream.

For the little-endian SH771x kernels the driver has to byte-swap the RX/TX
buffers,  however yet unset physcial address from the TX descriptor is used
to call sh_eth_soft_swap(). Use 'skb->data' instead...

Fixes: 31fcb99d9958 ("net: sh_eth: remove __flush_purge_region")
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>