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-4.4 commit 6f4dec2b0c31 ("qcom:
qpnp-smb2: Reset switcher_power_ok irq count when USBIN_UV fires").

This change also fixes different coding style related warnings.

Change-Id: I4439e87955bd4907086db49e1c80295169fbeb46
Signed-off-by: Mayank Rana <mrana@codeaurora.org>