sch_htb: Allow HTB priority parameter in offload mode

The current implementation of HTB offload returns the EINVAL error
for unsupported parameters like prio and quantum. This patch removes
the error returning checks for 'prio' parameter and populates its
value to tc_htb_qopt_offload structure such that driver can use the
same.

Add prio parameter check in mlx5 driver, as mlx5 devices are not capable
of supporting the prio parameter when htb offload is used. Report error
if prio parameter is set to a non-default value.

Signed-off-by: Naveen Mamindlapalli <naveenm@marvell.com>
Co-developed-by: Rahul Rameshbabu <rrameshbabu@nvidia.com>
Signed-off-by: Rahul Rameshbabu <rrameshbabu@nvidia.com>
Signed-off-by: Hariprasad Kelam <hkelam@marvell.com>
Signed-off-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>