Update the llproto_names array to allow users to reference the mpls
protocol ids with the names 'mpls_uc' for unicast MPLS and 'mpls_mc' for
multicast.
Signed-off-by: John Hurley <john.hurley@netronome.com> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: David Ahern <dsahern@gmail.com>