net/mlx5: fix eCPRI matching

net/mlx5: fix eCPRI matching

When an ETH or VLAN flow item directly preceding ECPRI (i. e. a pattern
for eCPRI over Ethernet) did not specify the eCPRI protocol, matches
were not restricted to eCPRI traffic. For example, "eth / ecpri / end"
pattern behaved as "eth / end". Implicitly add Ethernet type condition,
so that "eth / ecpri / end" behaves as "eth type is 0xAEFE / end".

Fixes: daa38a8924a0 ("net/mlx5: add flow translation of eCPRI header")
Cc: stable@dpdk.org
Signed-off-by: Dmitry Kozlyuk <dkozlyuk@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>