sfc: fix IPID endianness in TSOv2
The value we read from the header is in network byte order, whereas
EFX_POPULATE_QWORD_* takes values in host byte order (which it then
converts to little-endian, as MCDI is little-endian).
Fixes: e9117e5099ea ("sfc: Firmware-Assisted TSO version 2")
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>