xhci: Add a separate debug message for split transaction errors.

Don't show the same error message for transaction errors and split
transaction errors. It's very confusing while debugging.

Transaction errors are often due to electrical interference.
Split transaction errors are about xHC not being able to
schedule start and complete split transactions needed to address
low- and full-speed devices behind high-speed hubs.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20200312144517.1593-3-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/xhci-ring.c

@@ -2413,6 +2413,10 @@ static int handle_tx_event(struct xhci_hcd *xhci,
 		status = -EPIPE;
 		break;
 	case COMP_SPLIT_TRANSACTION_ERROR:
+		xhci_dbg(xhci, "Split transaction error for slot %u ep %u\n",
+			 slot_id, ep_index);
+		status = -EPROTO;
+		break;
 	case COMP_USB_TRANSACTION_ERROR:
 		xhci_dbg(xhci, "Transfer error for slot %u ep %u on endpoint\n",
 			 slot_id, ep_index);