cpufreq/amd-pstate: Fix cpufreq_policy ref counting

amd_pstate_update_limits() takes a cpufreq_policy reference but doesn't
decrement the refcount in one of the exit paths, fix that.

Fixes: 45722e7 ("cpufreq: amd-pstate: Optimize amd_pstate_update_limits()")
Signed-off-by: Dhananjay Ugwekar <dhananjay.ugwekar@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20250205112523.201101-10-dhananjay.ugwekar@amd.com
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>

Author: dhananjay-AMD

drivers/cpufreq/amd-pstate.c

@@ -821,20 +821,21 @@ static void amd_pstate_init_prefcore(struct amd_cpudata *cpudata)
 
 static void amd_pstate_update_limits(unsigned int cpu)
 {
-	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
+	struct cpufreq_policy *policy = NULL;
 	struct amd_cpudata *cpudata;
 	u32 prev_high = 0, cur_high = 0;
 	int ret;
 	bool highest_perf_changed = false;
 
+	if (!amd_pstate_prefcore)
+		return;
+
+	policy = cpufreq_cpu_get(cpu);
 	if (!policy)
 		return;
 
 	cpudata = policy->driver_data;
 
-	if (!amd_pstate_prefcore)
-		return;
-
 	guard(mutex)(&amd_pstate_driver_lock);
 
 	ret = amd_get_highest_perf(cpu, &cur_high);