dmaengine: k3dma: fix non-cyclic mode

Commit 36387a2b ("k3dma: Fix
memory handling in preparation for cyclic mode") broke the
logic around ds_run/ds_done in case of non-cyclic DMA.

This went unnoticed as the only user of k3dma was the i2s
audio driver but, with a patch set to enable dma on SPI, the
issue popped out.

The fix re-applies the initialization to ds_run/ds_done in
k3_dma_start_txd() that were removed by the commit above.

Also, one of the calls to k3_dma_start_txd() is triggered by
(ds_done != NULL), so remove the noisy and useless call to
WARN_ON_ONCE().
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/k3dma.c

@@ -275,12 +275,14 @@ static int k3_dma_start_txd(struct k3_dma_chan *c)
 		list_del(&ds->vd.node);
 
 		WARN_ON_ONCE(c->phy->ds_run);
-		WARN_ON_ONCE(c->phy->ds_done);
 		c->phy->ds_run = ds;
+		c->phy->ds_done = NULL;
 		/* start dma */
 		k3_dma_set_desc(c->phy, &ds->desc_hw[0]);
 		return 0;
 	}
+	c->phy->ds_run = NULL;
+	c->phy->ds_done = NULL;
 	return -EAGAIN;
 }