workqueue: Fix possible memory leaks in wq_numa_init()

In error handling branch "if (WARN_ON(node == NUMA_NO_NODE))", the
previously allocated memories are not released. Doing this before
allocating memory eliminates memory leaks.

tj: Note that the condition only occurs when the arch code is pretty broken
and the WARN_ON might as well be BUG_ON().

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>