ARM: dts: msm: Add avtimer for mpq8092

Avtimer driver is needed to support DVB usecases. Avtimer snapshots are
used to timestamp input frames and PCRs.

Change-Id: I12449f6a17e138d7f70e5634ae4c3c39cf676a4c
Signed-off-by: Prakash Gupta <guptap@codeaurora.org>