ARM: dts: msm: Add a dummy clock node for CPU clocks on MSMSKUNK

Support drivers needing references to the CPU clocks by
registering these clocks with the dummy clock controller.

Change-Id: I2faa8d601fc8fe418c32a7ccbea68a3b10428f91
Signed-off-by: Deepak Katragadda <dkatraga@codeaurora.org>