[ACPI] Export /sys/module/processor/parameters/max_cstate

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.de>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/processor_idle.c

@@ -55,7 +55,7 @@ ACPI_MODULE_NAME                ("acpi_processor")
 #define C3_OVERHEAD			4	/* 1us (3.579 ticks per us) */
 
 static void (*pm_idle_save)(void);
-module_param_named(max_cstate, max_cstate, uint, 0);
+module_param_named(max_cstate, max_cstate, uint, 0644);
 
 /* --------------------------------------------------------------------------
                                 Power Management