net/mlx5: fix link speed bitmasks

The constant ETHTOOL_LINK_MODE_1000baseT_Full_BIT and the others like
that in mlx5_link_update_unlocked_gs must be bit masks but unfortunately
they are bit numbers. This commit fixes the issue.

Fixes: 188408719888 ("net/mlx5: fix support for newer link speeds")
Cc: stable@dpdk.org
Signed-off-by: Edward Makarov <makarov@kraftway.ru>
Acked-by: Nelio Laranjeiro <nelio.laranjeiro@6wind.com>