dmaengine: idxd: Flush kernel workqueues on Function Level Reset

dmaengine: idxd: Flush kernel workqueues on Function Level Reset

When a Function Level Reset (FLR) happens, terminate the pending
descriptors that were issued by in-kernel users and disable the
interrupts associated with those. They will be re-enabled after FLR
finishes.

idxd_wq_flush_desc() is declared on idxd.h because it's going to be
used in by the DMA backend in a future patch.

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://patch.msgid.link/20260121-idxd-fix-flr-on-kernel-queues-v3-v3-4-7ed70658a9d1@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>