cpufreq: limit the scope of l_p_j variables

These variables are just used within adjust_jiffies() and so must be
local to it. Also there is no need of a dummy routine for CONFIG_SMP
case as we can take care of all that with help of macros in the same
routine. It doesn't look that ugly.

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