net/mlx5: Rename and move mlx5_esw_query_vport_vhca_id

Rename mlx5_esw_query_vport_vhca_id to mlx5_vport_get_vhca_id and move
it to vport file. Also, add function declaration to mlx5_core header
file. This better represents the function's usage and allows for it to
be called from other parts of the mlx5_core driver.

Signed-off-by: Akiva Goldberger <agoldberger@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20250209101716.112774-10-tariqt@nvidia.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>