We currently assume that the DMA Slave Config will be fully populated
by the platform, however some DMA Engines make decisions based on zero
(default) flags such as DMA_SLAVE_BUSWIDTH_UNDEFINED and as this is a
static declaration we need to memset it to clear the data area.
Signed-off-by: Lee Jones <lee.jones@linaro.org> Acked-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Mark Brown <broonie@linaro.org>