dmaengine: rcar-hpbdma: tidyup residue_granularity

The driver doesn't support residue reporting at all.
residue_granularity should be set to DMA_RESIDUE_GRANULARITY_DESCRIPTOR.
Special thanks to Laurent

Reported-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>