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-4.19 kernel commit <b318a6e04625>
("Merge "msm: ipa4: Fix to use common PM handle for coalescing and
default pipe"").

Change-Id: I07919f9453552bec5e420afad32a1bc65c761fd7
Signed-off-by: Mayank Rana <mrana@codeaurora.org>