cpufreq: governor: Remove unnecessary bits from print message

pr_*() helpers already prefix the print messages with
"cpufreq_governor:" and similar details aren't required in the actual
message.

For example, the print message getting fixed looks like this before this
patch:

cpufreq_governor: cpufreq: Governor initialization failed (dbs_data kobject init error 0)

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>