msm: usbaudio: Add support for USB headset detection

 - During bootup, create a file system storing the
   information about usb device state and name, and
   broadcast the message to userspace whenever the
   device is plugged or unplugged.

 - Register the device at USB sound card initialization
   for creating file system and toggle the state in that
   filesystem when USB is plugged/unplugged. This will
   also send a message to user space informing it about
   state change.

Change-Id: Icd78273bb765a26bbc70725afebe8955de8f7315
Signed-off-by: Harmandeep Singh <hsingh@codeaurora.org>

msm: usbaudio: Fix memory allocation for USB audio module init

Fix memory allocation issue in snd_usb_audio_init()
use sizeof(struct) insead of sizeof(pointer)

Change-Id: I270bbd7111e97dd4e0e92378f61d5025e16f5fca
Signed-off-by: Alex Fradkin <afradkin@codeaurora.org>

ASoC: usb: move the switch setting to more appropriate location

There is a delay between creation of sound card and creating of
corresponding steam. Currently we set the switch at the time of
creation of card. And later streams get created, so its more
optimal if we set the switch only after creating the stream.

Change-Id: Ic9f29d7a8dbcd32cde0097289ce6e1404a837372
Signed-off-by: Asish Bhattacharya <asishb@codeaurora.org>
usbaudio: update from Linux 3.4

Change-Id: I389cfc20e1856700781c65465947319cf09cf7cd
Signed-off-by: zwliew <zhaoweiliew@gmail.com>