usb: gadget: Add snapshot of USB QDSS Function driver

This change adds USB QDSS function driver which allows communication
between USB BAM and QDSS BAM for QDSS debug functionality over USB.
This snapshot is taken as of msm-4.14 commit <f6f026ce> ("Merge
"soc: qcom: sysmon-qmi: Fix duplicate BEFORE_POWERUP SSCTL events"").

Change-Id: If322e3a73b4e769d42a4bd6366ee62a0b39cd338
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>