USB xHCI: handle_tx_event() refactor: process_bulk_intr_td

This patch moves the bulk and interrupt td processing part in
handle_tx_event() into a separate function process_bulk_intr_td().

Signed-off-by: Andiry Xu <andiry.xu@amd.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>