ARM: dts: msm: Add AV timer specific data for APQ8084

LPASS exposes registers from which timestamp can be
read by clients for audio & video synchronization.
Change adds the register addresses of AV timer in LPASS.

Change-Id: I2a18a3e26131c57bf9c575842e21b3ca5d211918
Signed-off-by: Banajit Goswami <bgoswami@codeaurora.org>