net/e1000: fix missing Tx multi-segs capability

net/e1000: fix missing Tx multi-segs capability

In former API, ETH_TXQ_FLAGS_NOMULTSEGS was merely a hint indicating
that application will never send multisegmented packets, allowing
pmd to choose different tx methods accordingly.
In new API, DEV_TX_OFFLOAD_MULTI_SEGS became an offload capability
that is advertised by pmds, some of them do not advertise it and
expect to never receive fragmented packets (octeontx, axgbe)
So an ethdev that supports multisegmented packets should properly
advertise it.

Fixes: e5c05e6590ea ("net/e1000: convert to new Tx offloads API")
Cc: stable@dpdk.org
Signed-off-by: Didier Pallard <didier.pallard@6wind.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>