ANDROID: usb: gadget: f_accessory: Add Android Accessory function

USB accessory mode allows users to connect USB host hardware
specifically designed for Android-powered devices. The accessories
must adhere to the Android accessory protocol outlined in the
http://accessories.android.com

 documentation. This allows
Android devices that cannot act as a USB host to still interact with
USB hardware. When an Android device is in USB accessory mode, the
attached Android USB accessory acts as the host, provides power
to the USB bus, and enumerates connected devices.

Bug: 63740241
Bug: 120441124
Change-Id: I67964b50d278f3c0471d47efbb7b0973a3502681
[badhri: f_accessory is being migrated to userspace.]
Signed-off-by: Mike Lockwood <lockwood@android.com>
[AmitP: Folded following android-4.9 commit changes into this patch
        ceb2f0aac624 ("ANDROID: usb: gadget: accessory: Fix section mismatch")
        Parts of e27543931009 ("ANDROID: usb: gadget: Fixes and hacks to make android usb gadget compile on 3.8")
        1b07ec751563 ("ANDROID: drivers: usb: gadget: 64-bit related type fixes")]
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
[astrachan: Folded the following changes into this patch:
            9d5891d516e2 ("ANDROID: usb: gadget: f_accessory: Add ACCESSORY_SET_AUDIO_MODE control request and ioctl")
            dc66cfce9622 ("ANDROID: usb: gadget: f_accessory: Add support for HID input devices")
            5f1ac9c2871b ("ANDROID: usb: gadget: f_accessory: move userspace interface to uapi")
            9a6241722cd8 ("ANDROID: usb: gadget: f_accessory: Enabled Zero Length Packet (ZLP) for acc_write")
            31a0ecd5a825 ("ANDROID: usb: gadget: f_accessory: check for accessory device before disconnecting HIDs")
            580721fa6cbc ("ANDROID: usb: gadget: f_accessory: Migrate to USB_FUNCTION API")
            7f407172fb28 ("ANDROID: usb: gadget: f_accessory: Fix for UsbAccessory clean unbind.")
            ebc98ac5a22f ("ANDROID: usb: gadget: f_accessory: fix false disconnect due to a signal sent to the reading process")
            71c6dc5ffdab ("ANDROID: usb: gadget: f_accessory: assign no-op request complete callbacks")
            675047ee68e9 ("ANDROID: usb: gadget: f_accessory: Move gadget functions code")
            b2bedaa5c7df ("CHROMIUM: usb: gadget: f_accessory: add .raw_request callback")]
Signed-off-by: Alistair Strachan <astrachan@google.com>