usb: musb: musb_cppi41: Dont reprogram DMA if tear down is initiated

Reprogramming the DMA after tear down is initiated leads to warning.
This is mainly seen with ISOCH since we do a delayed completion for
ISOCH transfers. In ISOCH transfers dma_completion should not reprogram
if the channel tear down is initiated.
Signed-off-by: George Cherian <george.cherian@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/musb/musb_cppi41.c

@@ -132,7 +132,8 @@ static void cppi41_trans_done(struct cppi41_dma_channel *cppi41_channel)
 	struct musb_hw_ep *hw_ep = cppi41_channel->hw_ep;
 	struct musb *musb = hw_ep->musb;
 
-	if (!cppi41_channel->prog_len) {
+	if (!cppi41_channel->prog_len ||
+	    (cppi41_channel->channel.status == MUSB_DMA_STATUS_FREE)) {
 
 		/* done, complete */
 		cppi41_channel->channel.actual_len =