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>
diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index 7e14d5a..a98493c 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -61,9 +61,9 @@
 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