net/mlx5: fix probe failure report

net/mlx5: fix probe failure report

The corrupted code doesn't return error when probe function
fails due to error in device mac address getting.
By this way, the probe function may return success even if the
ETH dev is not allocated.

Hence, the probe caller, for example failsafe PMD, fails when it
tries to get ETH dev after the device was plugged out while mlx5
was probing it.

The fix adds error report to the probe caller when priv_get_mac fails
and in all other failure options which are missing it.

By this way, it prevents the unexpected behavior to miss ETH device
after the device was probed successfully.

This bug was already present in the original code taken from mlx4.

Fixes: 771fa900b73a ("mlx5: introduce new driver for Mellanox ConnectX-4 adapters")
Fixes: 1371f4df16bc ("mlx5: check port is configured as ethernet device")
Cc: stable@dpdk.org
Signed-off-by: Matan Azrad <matan@mellanox.com>
Acked-by: Nelio Laranjeiro <nelio.laranjeiro@6wind.com>