ARM: EXYNOS: Set the capability of pdm0 and pdm1 as DMA_PRIVATE

DMA clients pdma0 and pdma1 are internal to the SoC and are used only
by dedicated peripherals. Since they cannot be used for generic
purpose, their capability should be set as DMA_PRIVATE.

CC: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>