drivers: mcb: use symbol namespaces

Now that we have symbol namespaces, use them in MCB to not pollute the
default namespace with MCB internals.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Jessica Yu <jeyu@kernel.org>
Reviewed-by: Michael Moese <mmoese@suse.de>
Link: https://lore.kernel.org/r/20191016100158.1400-1-jthumshirn@suse.de


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>