cpufreq: amd-pstate: remove unused variable lowest_nonlinear_freq

removed the unused variable `lowest_nonlinear_freq` for build warning.
This variable was defined and assigned a value in the previous code,
but it was not used in the subsequent code.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202404271038.em6nJjzy-lkp@intel.com/
Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: Perry Yuan

drivers/cpufreq/amd-pstate.c

@@ -878,7 +878,7 @@ static int amd_pstate_init_freq(struct amd_cpudata *cpudata)
 
 static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
 {
-	int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret;
+	int min_freq, max_freq, nominal_freq, ret;
 	struct device *dev;
 	struct amd_cpudata *cpudata;
 
@@ -910,7 +910,6 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
 	min_freq = READ_ONCE(cpudata->min_freq);
 	max_freq = READ_ONCE(cpudata->max_freq);
 	nominal_freq = READ_ONCE(cpudata->nominal_freq);
-	lowest_nonlinear_freq = READ_ONCE(cpudata->lowest_nonlinear_freq);
 
 	if (min_freq <= 0 || max_freq <= 0 ||
 	    nominal_freq <= 0 || min_freq > max_freq) {
@@ -1339,7 +1338,7 @@ static bool amd_pstate_acpi_pm_profile_undefined(void)
 
 static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
 {
-	int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret;
+	int min_freq, max_freq, nominal_freq, ret;
 	struct amd_cpudata *cpudata;
 	struct device *dev;
 	u64 value;
@@ -1373,7 +1372,6 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
 	min_freq = READ_ONCE(cpudata->min_freq);
 	max_freq = READ_ONCE(cpudata->max_freq);
 	nominal_freq = READ_ONCE(cpudata->nominal_freq);
-	lowest_nonlinear_freq = READ_ONCE(cpudata->lowest_nonlinear_freq);
 	if (min_freq <= 0 || max_freq <= 0 ||
 	    nominal_freq <= 0 || min_freq > max_freq) {
 		dev_err(dev,