ARM: dts: msm: Add support for speed-bin 3 for SDM660

Add speed-bin 3 to support the fmax of 1.8 GHz and 1.6 GHz
for perf and power clusters respectively.
And also update the cpufreq table for the same.

Change-Id: Ia3be3f321b53bbbb4c37f5e86e451ca86ec8cdc9
Signed-off-by: Odelu Kukatla <okukatla@codeaurora.org>