dmaengine: ti: edma: fix missed failure handling

dmaengine: ti: edma: fix missed failure handling

[ Upstream commit 340049d453682a9fe8d91fe794dd091730f4bb25 ]

When devm_kcalloc fails, it forgets to call edma_free_slot.
Replace direct return with failure handler to fix it.

Fixes: 1be5336bc7ba ("dmaengine: edma: New device tree binding")
Signed-off-by: Chuhong Yuan <hslester96@gmail.com>
Link: https://lore.kernel.org/r/20191118073802.28424-1-hslester96@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>