usb: misc: Add snapshot of diag_ipc_bridge driver

Add diag_ipc_bridge driver which is used to communicate with the diag
and QMI interfaces exposed by Qualcomm devices. This snapshot is
taken as of msm-4.14 'commit 9f6f3a7d1aa9 ("msm: kgsl: Perform cache flush
on the pages obtained using get_user_pages()")'.

Change-Id: I8d5069d40b623b2a06eb3eb45a8c5fca1769222a
Signed-off-by: Vijayavardhan Vennapusa <quic_vvreddy@quicinc.com>