usb: gadget: u_audio: update hw_ptr in iso_complete after data copied

usb: gadget: u_audio: update hw_ptr in iso_complete after data copied

In u_audio_iso_complete, the runtime hw_ptr is updated before the
data is actually copied over to/from the buffer/dma area. When
ALSA uses this hw_ptr, the data may not actually be available to
be used. This causes trash/stale audio to play/record. This
patch updates the hw_ptr after the data has been copied to avoid
this.

Change-Id: I94736e4ea899ac781076e9c425dda65eed7cc319
Fixes: 132fcb460839 ("usb: gadget: Add Audio Class 2.0 Driver")
Signed-off-by: Joshua Frkuska <joshua_frkuska@mentor.com>
Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Git-commit: 6b37bd78d30c890e575a1bda22978d1d2a233362
Git-repo: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Ajay Agarwal <ajaya@codeaurora.org>