cpufreq: sa11x0: Fix build breakage after "Expose frequency table"

Fix build breakage introduced by commit 22c8b4f1 (cpufreq: sa11x0:
Expose frequency table).

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