ALSA: usb-audio: Use rwsem for disconnect protection
Replace mutex with rwsem for codec->shutdown protection so that
concurrent accesses are allowed.

Also add the protection to snd_usb_autosuspend() and
snd_usb_autoresume(), too.

Signed-off-by: sndnvaps <sndnvaps@gmail.com>
Merge branch 'phablet-saucy' of github.com:sndnvaps/android_kernel_samsung_crespo into phablet-saucy