msm: cpufreq: Remove unused msm_cpufreq_set_freq_limits() API

The msm_cpufreq_set_freq_limits() is a mach specific way to set CPU freq
limits. The thermal code no longer uses this API and instead uses the
standard INCOMPATIBLE notifiers provided by the common CPUfreq framework.
Since this API is no longer needed, delete it.

Change-Id: I5c07b17195d4e4b75cdd4d82f8e7cb6cb6f3e199
Signed-off-by: Saravana Kannan <skannan@codeaurora.org>