adbd: Add os descriptor support for adb.

Eventhough windows does not rely on extended os
descriptor for adbd, when android usb device is
configures as a composite device such as mtp+adb,
windows discards the extended os descriptor even
if one of the USB function fails to send
the extended compat descriptor. This results in automatic
install of MTP driverto fail when Android device is in
"File Transfer" mode with adb enabled.

https://msdn.microsoft.com/en-us/library/windows/hardware/gg463179.aspx

BUG=24583401
BUG=chromium:43409

Change-Id: I87341683a9337848cac66daf9055b0d05cedd3d3