Modify UsbDeviceManager stack to allow MtpServer to use FunctionFS drivers.

Functionfs requires MtpServer to write descriptors before the device can be
configured. This adds a new configure call that will occur only when
functions are changed (new argument added to updateUsbStateBroadcast for this)
and be called after sys.usb.config is changed but before the waitForState
call to ensure compatibility with configfs devices.

Bug: 30976142
Change-Id: I7e94a5847d3b19c0fd75139e1b15a3f2a1cea01d
Test: Manual