net/mlx5e: Add PTP Flow Steering support

When opening PTP channel with MLX5E_PTP_STATE_RX set, add the
corresponding flow steering rules. Capture UDP packets with destination
port 319 and L2 packets with ethertype 0x88F7 and steer them into the RQ
of the PTP channel.
Add API that manages the flow steering rules to be used in the following
patches via safe_reopen_channels mechanism.

Signed-off-by: Aya Levin <ayal@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>