omap: SDMA: Fix omap_stop_dma() API for channel linking

omap: SDMA: Fix omap_stop_dma() API for channel linking

OMAP sDMA driver API omap_stop_dma() doesn't really stop the dma when used
in linking scenario.

The DMA channel needs to be disabled before resetting the chain.
Also fix clearing of the OMAP_DMA_ACTIVE status in the linked case.

Cc: Hari n <[email protected]>
Cc: Jarkko Nikula <[email protected]>
Signed-off-by: Santosh Shilimkar <[email protected]>
Signed-off-by: Venkatraman S <[email protected]>
Signed-off-by: Tony Lindgren <[email protected]>