mcb: fix error handling in mcb_alloc_bus()
This is an automated ID intended to aid in discovery of potential security vulnerabilities. The actual impact and attack plausibility have not yet been proven. This ID is fixed in Linux Kernel version v4.19.209 by commit 66f74ba9be9daf9c47fface6af3677f602774f6b, it was introduced in version v4.7 by commit 5d9e2ab9fea4cdf0a2522f5cbed2e7fbb220d757. For more details please see the references link.