dmaengine: xilinx: dpdma: Fix descriptor issuing on video group

dmaengine: xilinx: dpdma: Fix descriptor issuing on video group

[ Upstream commit 1cbd44666216278bbb6a55bcb6b9283702171c77 ]

When multiple channels are part of a video group, the transfer is
triggered only when all channels in the group are ready. The logic to do
so is incorrect, as it causes the descriptors for all channels but the
last one in a group to not being pushed to the hardware. Fix it.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/20210307040629.29308-2-laurent.pinchart@ideasonboard.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>