mlxsw: Add ubridge to config profile

The unified bridge model is enabled via the CONFIG_PROFILE command
during driver initialization. Add the definition of the relevant fields
to the command's payload in preparation for unified bridge enablement.

Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>