USB: gadget: android Fix gadget descriptor compliance for IAD's

USB: gadget: android Fix gadget descriptor compliance for IAD's

USB-IF core team mandates that composite devices containing
IAD's must use bDeviceClass=0xEF, bDeviceSubClass=0x02, &
bDeviceProtocol=0x01 instead of the usual 0x00 in all fields.
This is not a problem currently on Linux hosts, but it is a
problem when connecting to Windows hosts. Without this change
the default Microsoft composite driver will not group
interfaces properly, which is what allows child function
drivers with IAD's to load correctly.

Signed-off-by: Mike Lockwood <lockwood@android.com>