In the case of tunnel packet, PKT_RX_{IP,L4}_CSUM_* flags correspond
to inner packet checksums. There is only one flag to indicate bad
external IPv4 header checksum.
Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
Reviewed-by: Ivan Malov <ivan.malov@oktetlabs.ru>