cpufreq: amd_freq_sensitivity: Mark sometimes used ID structs as __maybe_unused

ot used when MODULE is not defined.

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

 drivers/cpufreq/amd_freq_sensitivity.c:147:32: warning: ‘amd_freq_sensitivity_ids’ defined but not used [-Wunused-const-variable=]
 147 | static const struct x86_cpu_id amd_freq_sensitivity_ids[] = {
 | ^~~~~~~~~~~~~~~~~~~~~~~~

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>