dmaengine: idxd: fix wq conf_dev 'struct device' lifetime

Remove devm_* allocation and fix wq->conf_dev 'struct device' lifetime.
Address issues flagged by CONFIG_DEBUG_KOBJECT_RELEASE. Add release
functions in order to free the allocated memory for the wq context at
device destruction time.

Reported-by: Jason Gunthorpe <jgg@nvidia.com>
Fixes: bfe1d560

 ("dmaengine: idxd: Init and probe for Intel data accelerators")
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/161852985907.2203940.6840120734115043753.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>