ACPI: Cleanup custom_method debug stuff

- Move param aml_debug_output to other params into sysfs.c
- Split acpi_debugfs_init to prepare custom_method to be
  an own .config option and driver.

Signed-off-by: Thomas Renninger <trenn@suse.de>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: rui.zhang@intel.com
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 4bfb759d..ca75b9c 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -28,9 +28,10 @@
 int acpi_sysfs_init(void);
 
 #ifdef CONFIG_DEBUG_FS
+extern struct dentry *acpi_debugfs_dir;
 int acpi_debugfs_init(void);
 #else
-static inline int acpi_debugfs_init(void) { return 0; }
+static inline void acpi_debugfs_init(void) { return; }
 #endif
 
 /* --------------------------------------------------------------------------