ARM: dts: msmcobalt: add status property for memlat-mon for msmcobalt

Set the status property of the qcom,memlat-mon-cpu4 device. This is
required for partial binned devices.

Change-Id: I246a5f5149e492aba4f7c3920296d4bd3d873de0
Signed-off-by: David Keitel <dkeitel@codeaurora.org>