cpufreq: pasemi: Include header file for {check,restore}_astate prototypes

If function callers and providers do not share the same prototypes the
compiler complains of missing prototypes.  Fix this by including the
correct platforms header file.

Fixes the following W=1 kernel build warning(s):

 drivers/cpufreq/pasemi-cpufreq.c:109:5: warning: no previous prototype for ‘check_astate’ [-Wmissing-prototypes]
 109 | int check_astate(void)
 | ^~~~~~~~~~~~
 drivers/cpufreq/pasemi-cpufreq.c:114:6: warning: no previous prototype for ‘restore_astate’ [-Wmissing-prototypes]
 114 | void restore_astate(int cpu)
 | ^~~~~~~~~~~~~~

Suggested-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>