bus: mhi: ep: Demote unsupported channel error log to debug

Not all MHI endpoints will support all available channels. Most of them
support only a selected number of channels based on the implementations.
In those cases, it is not needed to print error messages in the endpoint.
So let's demote the error log to debug.
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

drivers/bus/mhi/ep/main.c

@@ -126,7 +126,7 @@ static int mhi_ep_process_cmd_ring(struct mhi_ep_ring *ring, struct mhi_ring_ele
 
 	/* Check if the channel is supported by the controller */
 	if ((ch_id >= mhi_cntrl->max_chan) || !mhi_cntrl->mhi_chan[ch_id].name) {
-		dev_err(dev, "Channel (%u) not supported!\n", ch_id);
+		dev_dbg(dev, "Channel (%u) not supported!\n", ch_id);
 		return -ENODEV;
 	}
 
@@ -702,7 +702,7 @@ static void mhi_ep_cmd_ring_worker(struct work_struct *work)
 		el = &ring->ring_cache[ring->rd_offset];
 
 		ret = mhi_ep_process_cmd_ring(ring, el);
-		if (ret)
+		if (ret && ret != -ENODEV)
 			dev_err(dev, "Error processing cmd ring element: %zu\n", ring->rd_offset);
 
 		mhi_ep_ring_inc_index(ring);