net/mlx5: Fix rate limit packet pacing naming and struct

In mlx5_ifc, struct size was not complete, and thus driver was sending
garbage after the last defined field. Fixed it by adding reserved field
to complete the struct size.

In addition, rename all set_rate_limit to set_pp_rate_limit to be
compliant with the Firmware <-> Driver definition.

Fixes: 7486216b ("{net,IB}/mlx5: mlx5_ifc updates")
Fixes: 1466cc5b ("net/mlx5: Rate limit tables support")
Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>