pch_dma: Fix DMA setting issue

Currently, Direct-Start mode(*) is enabled.
Our IOH's devices must not use this mode.
This causes unexpected behavior.
This patch deletes Direct-Start setting.
(*) This mode is used in order for CPU to generate the DMA request.

Signed-off-by: Tomoya MORINAGA <tomoya-linux@dsn.okisemi.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>