ARM: dts: msm: enable memory-mapped timer

Enable the memory-mapped timer to support the high resolution timer.

Change-Id: I6bc956dd6881c803ea3982e1a06a308741128ed9
Acked-by: Jie Luo <jluo@qti.qualcomm.com>
Signed-off-by: Niranjana Vishwanathapura <nvishwan@codeaurora.org>