coresight-tmc-etr: remove mem_lock when call usb_qdss_close

This mem_lock will cause deadlock when usb close router call back to
usb_notifier. so remove it.

Change-Id: I9530c843702ca605f6935cc0ac6d9649bf204594
Signed-off-by: Yuanfang Zhang <zhangyuanfang@codeaurora.org>