Add missing IP Fragmentation Flag.

Fixes: f9358e12 ("net: mvpp2: split ingress traffic into multiple flows")
Signed-off-by: Sven Auhagen <sven.auhagen@voleatech.de>
Reviewed-by: Marcin Wojtas <mw@semihalf.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>