Tenderloin: Fix buzz and reboot issue while screen is off

Fixes an issue when not plugged into usb and playing audio
while the screen is sleeping causes a kernel panic and
reboot.  The issue lies in closing out uart and logging
it.  This is a temp fix until a more permanent one is
found.

Change-Id: Id564d6b3c92e430f478f24fe9b53bec909fb6db0