blk-mq: fix possible memleak when register 'hctx' failed
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 v4.9.337 by commit 654870789c3c1b9763316ef1c71d7a449127b175. For more details please see the references link.