regmap: Remove warning on stubbed dev_get_regmap()

It's perfectly sensible to ask if there's a regmap for a device which
doesn't have one so the stubbed version shouldn't complain, the caller
should be prepared for this.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

include/linux/regmap.h

@@ -386,7 +386,6 @@ static inline int regmap_register_patch(struct regmap *map,
 static inline struct regmap *dev_get_regmap(struct device *dev,
 					    const char *name)
 {
-	WARN_ONCE(1, "regmap API is disabled");
 	return NULL;
 }