cpufreq: governor: name pointer to cpu_dbs_info as 'cdbs'

It is called as 'cdbs' at most of the places and 'cpu_dbs' at others.
Lets use 'cdbs' consistently for better readability.

Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>