This adds a QAPI schema for the properties of the can-* objects.

can-bus doesn't have any properties, so it only needs to be added to the
ObjectType enum without adding a new branch to ObjectOptions.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>