dmaengine: ti: k3-udma: Fix delayed_work usage for tx drain workaround

dmaengine: ti: k3-udma: Fix delayed_work usage for tx drain workaround

INIT_DELAYED_WORK_ONSTACK() must be used with on-stack delayed work, which
is not the case here.
Use normal delayed_work for the channels instead.

Fixes: 25dcb5dd7b7c ("dmaengine: ti: New driver for K3 UDMA")
Reported-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Link: https://lore.kernel.org/r/20200618114004.6268-1-peter.ujfalusi@ti.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>