dmaengine: rcar-dmac: warn if transfer cannot start as TE = 1

The documentation states one should make sure both DE and TE are cleared
before starting a transaction. This patch extends the current warning to
look at both DE and TE.

Based on previous work from Muhammad Hamza Farooq.

Suggested-by: Muhammad Hamza Farooq <mfarooq@visteon.com>
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/sh/rcar-dmac.c

@@ -311,7 +311,7 @@ static bool rcar_dmac_chan_is_busy(struct rcar_dmac_chan *chan)
 {
 	u32 chcr = rcar_dmac_chan_read(chan, RCAR_DMACHCR);
 
-	return (chcr & (RCAR_DMACHCR_DE | RCAR_DMACHCR_TE)) == RCAR_DMACHCR_DE;
+	return !!(chcr & (RCAR_DMACHCR_DE | RCAR_DMACHCR_TE));
 }
 
 static void rcar_dmac_chan_start_xfer(struct rcar_dmac_chan *chan)