ARM: dts: msm: Add cpufreq node for FSM9900 target

Add the cpufreq operating frequency node to the
device tree for FSM9900 targets.

Change-Id: I22b9cbe44a4e5bd6b521ed021916707465020fea
Acked-by: Kaushik Sikdar <ksikdar@qti.qualcomm.com>
Signed-off-by: Rohit Vaswani <rvaswani@codeaurora.org>