cpufreq: intel_pstate: Fix missing return statement

Fix missing return statement when writing "off" to intel_pstate status
sysfs I/F.

Fixes: 55671ea325 ("cpufreq: intel_pstate: Free memory only when turning off")
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/intel_pstate.c

@@ -2781,6 +2781,7 @@ static int intel_pstate_update_status(const char *buf, size_t size)
 
 		cpufreq_unregister_driver(intel_pstate_driver);
 		intel_pstate_driver_cleanup();
+		return 0;
 	}
 
 	if (size == 6 && !strncmp(buf, "active", size)) {