regmap: Allow drivers to control cache_only flag

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 63b3075..76ac255 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -141,4 +141,6 @@
 		       unsigned int mask, unsigned int val);
 
 int regcache_sync(struct regmap *map);
+void regcache_cache_only(struct regmap *map, bool enable);
+
 #endif