linux-imx

dmaengine: mid_dma: mask_peripheral_interrupt only when dmac is idle

The mask_peripheral_interrupt is called when channel wants to mask the
interrupt. Move this to suspend as this masking affects other channels
as well. Not touching unmask here and unmask would still be done of
first channel use

Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>