regmap: Make debugfs stubs static inline

Make the debugfs stubs static inline to avoid future compilation issues due to
duplicated symbols when CONFIG_DEBUG_FS=n once internal.h is included by
multiple source files.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/base/regmap/internal.h

@@ -61,9 +61,9 @@ extern void regmap_debugfs_initcall(void);
 extern void regmap_debugfs_init(struct regmap *map);
 extern void regmap_debugfs_exit(struct regmap *map);
 #else
-void regmap_debugfs_initcall(void) { }
-void regmap_debugfs_init(struct regmap *map) { }
-void regmap_debugfs_exit(struct regmap *map) { }
+static inline void regmap_debugfs_initcall(void) { }
+static inline void regmap_debugfs_init(struct regmap *map) { }
+static inline void regmap_debugfs_exit(struct regmap *map) { }
 #endif
 
 #endif