ARM: dts: qcom: Add Performance Monitor Unit Node Support For mdm9607

ARM cores often have a PMU for counting cpu and cache events like cache
misses and hits. The interface to the PMU is part of the ARM.

Change-Id: Ic7fd4a1a12dc453ef3bfee4107a06a23519452b2
Signed-off-by: Sagar Chormale <schormal@codeaurora.org>