ANDROID: sound: usb: Add vendor's hooking interface

In mobile, a co-processor can be used with USB audio to improve power
consumption.  To support this type of hardware, hooks need to be added
to the USB audio subsystem to be able to call into the hardware when
needed.

The main operation of the call-backs are:
  - Initialize the co-processor by transmitting data when initializing.
  - Change the co-processor setting value through the interface
    function.
  - Configure sampling rate
  - pcm open/close
  - other housekeeping

Known issues:
  - This only supports one set of callback hooks, meaning that this only
    works if there is one type of USB controller in the system.  This
    should be changed to be a per-host-controller interface instead of
    one global set of callbacks.

Bug: 156315379
Change-Id: I32e1dd408e64aaef68ee06c480c4b4d4c95546dc
Signed-off-by: JaeHun Jung <jh0801.jung@samsung.com>
[rework api to be a bit more self-contained and obvious - gregkh]
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>