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

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.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>