CVE-2023-54294

In the Linux kernel, the following vulnerability has been resolved:

md/raid10: fix memleak of md thread

In raid10_run(), if setup_conf() succeed and raid10_run() failed before
setting 'mddev->thread', then in the error path 'conf->thread' is not
freed.

Fix the problem by setting 'mddev->thread' right after setup_conf().