Add ACCESSORY_SET_AUDIO_MODE control request and ioctl

The control request will be used by the host to enable/disable USB audio
and the ioctl will be used by userspace to read the audio mode

Signed-off-by: Mike Lockwood <lockwood@google.com>
USB: gadget: f_accessory: Add support for HID input devices

Signed-off-by: Mike Lockwood <lockwood@google.com>
USB: gadget: f_audio_source: New gadget driver for audio
 output

This driver presents a standard USB audio class interface to the host
and an ALSA PCM device to userspace

Change-Id: I9c4c5da4caadd17d3dd155da0870024e84cb3345
Signed-off-by: Mike Lockwood <lockwood@google.com>
usb: gadget: composite: Fix corruption when changing configuration

Remove the config from the configs list before releasing the spinlock.
Otherwise the other cpu might be processing a SET_CONFIGURATION that
will switch to the configuration that is being released.

Bug: 6521576
Change-Id: Id4da0d0e18ead63e20cb236cd1d3e8e6d116acce
Signed-off-by: Benoit Goby <benoit@android.com>
USB: gadget: f_audio_source: Adjust packet timing to reduce glitches

Increase max packet size and clean up timing logic so we can better
recover from not getting an interrupt in time for a SOF.

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