dmaengine: sprd: Fix the right place to configure 2-stage transfer

Move the 2-stage configuration before configuring the link-list mode,
since we will use some 2-stage configuration to fill the link-list
configuration.

Signed-off-by: Eric Long <eric.long@unisoc.com>
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Vinod Koul <vkoul@kernel.org>