cpufreq: qcom-nvmem: fix compilation warning for qcom_cpufreq_ipq806x_match_list

If CONFIG_OF is not enabled, of_match_node() is set as NULL and
qcom_cpufreq_ipq806x_match_list won't be used causing a compilation
warning.

Flag qcom_cpufreq_ipq806x_match_list as __maybe_unused to fix the
compilation warning.

While at it also flag as __initconst as it's used only in probe contest
and can be freed after probe.

This follows the pattern of the usual of_device_id variables.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202511202119.6zvvFMup-lkp@intel.com/
Fixes: 58f5d39 ("cpufreq: qcom-nvmem: add compatible fallback for ipq806x for no SMEM")
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
[ Viresh: Drop __initconst ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

Author: Ansuel

drivers/cpufreq/qcom-cpufreq-nvmem.c

@@ -256,7 +256,7 @@ static int qcom_cpufreq_krait_name_version(struct device *cpu_dev,
 	return ret;
 }
 
-static const struct of_device_id qcom_cpufreq_ipq806x_match_list[] = {
+static const struct of_device_id qcom_cpufreq_ipq806x_match_list[] __maybe_unused = {
 	{ .compatible = "qcom,ipq8062", .data = (const void *)QCOM_ID_IPQ8062 },
 	{ .compatible = "qcom,ipq8064", .data = (const void *)QCOM_ID_IPQ8064 },
 	{ .compatible = "qcom,ipq8065", .data = (const void *)QCOM_ID_IPQ8065 },