usb: gadget: f_gsi: Add support for gps function driver

gps usb functionality is implemented using qmi packets.
User space entity sends and receives QMI packets using
misc device named /dev/gps.

Change-Id: I73af1caa9b272597909199022739390274a4b034
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>
Signed-off-by: Elson Roy Serrao <eserrao@codeaurora.org>