dmaengine: idxd: move interrupt handle assignment

dmaengine: idxd: move interrupt handle assignment

In preparation of supporting interrupt handle revoke event, move the
interrupt handle assignment to right before the descriptor to be submitted.
This allows the interrupt handle revoke logic to assign the latest
interrupt handle on submission.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/163528417767.3925689.7730411152122952808.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>