ARM: dts: msm: Add cpufreq support for sdxpoorwills

Add msm-cpufreq table and device for sdxpoorwills. This change allows for
proper cpu frequency voting and cpufreq sysfs entries.

Change-Id: I469364772ce2fb65206bd71ee78beabeb39e627e
Signed-off-by: Jonathan Avila <avilaj@codeaurora.org>