ARM: dts: msm: Add dummy cpu clocks for MSM8992

Add the DT entry for the dummy cpu clocks. Also modify the cpu
clock list as per the updated clock diagram.

Change-Id: I45f62b780ab6b9a47af1e4084c41af3873936380
Signed-off-by: Pushkar Joshi <pushkarj@codeaurora.org>