dmaengine: xilinx_dma: Fix control reg update in vdma_channel_set_config

dmaengine: xilinx_dma: Fix control reg update in vdma_channel_set_config

In vdma_channel_set_config clear the delay, frame count and master mask
before updating their new values. It avoids programming incorrect state
when input parameters are different from default.

Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
Acked-by: Appana Durga Kedareswara rao <appana.durga.rao@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/1569495060-18117-3-git-send-email-radhey.shyam.pandey@xilinx.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>