ARM: dts: msm: Add cpu capacity-dmips-mhz information for SDM855

Scheduler uses this information to distinguish between clusters
available on the system.

Change-Id: I5b26ddd7113d7abf826667904a459341c1cc4ad5
Signed-off-by: Satya Durga Srinivasu Prabhala <satyap@codeaurora.org>