dmaengine: imx-sdma: fix cyclic buffer race condition

Assign buffer ownership to SDMA after invoking descriptor callback to
make sure that SDMA does not write to the buffer before it is read by
the CPU.

Signed-off-by: Tomasz Moń <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

drivers/dma/imx-sdma.c

···
 		*/
 
 		desc->chn_real_count = bd->mode.count;
-		bd->mode.status |= BD_DONE;
 		bd->mode.count = desc->period_len;
 		desc->buf_ptail = desc->buf_tail;
 		desc->buf_tail = (desc->buf_tail + 1) % desc->num_bd;
···
 		spin_unlock(&sdmac->vc.lock);
 		dmaengine_desc_get_callback_invoke(&desc->vd.tx, NULL);
 		spin_lock(&sdmac->vc.lock);
+
+		/* Assign buffer ownership to SDMA */
+		bd->mode.status |= BD_DONE;
 
 		if (error)
 			sdmac->status = old_status;