net/mlx5: Rename devlink rate parent set function for leaf nodes

Rename `mlx5_esw_devlink_rate_parent_set()` to
`mlx5_esw_devlink_rate_leaf_parent_set()` to distinguish setting a
parent for leafs from nodes, which is not yet supported.

Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/1741642016-44918-2-git-send-email-tariqt@nvidia.com


Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>