ARM: dts: msm: Make m4m-hwmon available only on MSM8996v3

Hardware support for M4M HW monitor is only added in MSM8996v3. Move
device from msm8996.dtsi to msm8996-v3.dtsi. In addition, configure
the counter to track read and write events separately instead of
total counts.

Change-Id: I13e89de9c9e75b4e0643317593aea787529ef4a6
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>