avtimer: kernel driver to expose avtimer to userspace

avtimer clock is owned by Q6. avtimer clock tick is used by
mpqplayer, and vcap for implementation of avsync logic. This
character driver gets the Q6 out of power collapsed state and
exposes ioctl control to read avtimer tick.

Change-Id: Ic60dbe6a6bf2a4aed30ef89b63830575efd30083
Signed-off-by: Srikanth Uyyala <suyyala@codeaurora.org>