md: fix a lock order reversal in md_alloc
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 906b4dcc180808f0ba74ec1e07a5cf708463bc48, it was introduced in version v3.0 by commit b0140891a8cea36469f58d23859e599b1122bd37. For more details please see the references link.