net/mlx5: Add generic getters for other functions caps

Downstream patch requires to get other function GENERAL2 caps while
mlx5_vport_get_other_func_cap() gets only one type of caps (general).
Rename it to represent this and introduce a generic implementation
of mlx5_vport_get_other_func_cap().

Signed-off-by: Shay Drory <shayd@nvidia.com>
Reviewed-by: Mark Bloch <mbloch@nvidia.com>
Acked-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>