dmaengine: fsl-dpaa2-qdma: Fix error return code in two functions

Fix to return a negative error code from the error handling case instead
of 0, as done elsewhere in the function where it is.

Fixes: 7fdf9b05

 ("dmaengine: fsl-dpaa2-qdma: Add NXP dpaa2 qDMA controller driver for Layerscape SoCs")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/r/20210508030056.2027-1-thunder.leizhen@huawei.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>