dmaengine: idxd: Flush all pending descriptors

dmaengine: idxd: Flush all pending descriptors

When used as a dmaengine, the DMA "core" might ask the driver to
terminate all pending requests, when that happens, flush all pending
descriptors.

In this context, flush means removing the requests from the pending
lists, so even if they are completed after, the user is not notified.

Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Link: https://patch.msgid.link/20260121-idxd-fix-flr-on-kernel-queues-v3-v3-5-7ed70658a9d1@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>