bus: fsl-mc: export device types present on the bus

Export all device types present on the fsl-mc bus in order to be able to
actually use the is_fsl_mc_bus_*() functions from drivers on the bus.

Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>