cpufreq: amd-pstate: fix memory leak on CPU EPP exit

The cpudata memory from kzalloc() in amd_pstate_epp_cpu_init() is
not freed in the analogous exit function, so fix that.
Signed-off-by: Peng Ma <andypma@tencent.com>
Acked-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Perry Yuan <Perry.Yuan@amd.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/amd-pstate.c

@@ -1441,6 +1441,13 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
 
 static int amd_pstate_epp_cpu_exit(struct cpufreq_policy *policy)
 {
+	struct amd_cpudata *cpudata = policy->driver_data;
+
+	if (cpudata) {
+		kfree(cpudata);
+		policy->driver_data = NULL;
+	}
+
 	pr_debug("CPU %d exiting\n", policy->cpu);
 	return 0;
 }