regmap: cache: Move the num_reg_defaults check as early as possible

If the register defaults are provided by the driver without the
number by mistake, it should just return an error with one promotion.

This should be as early as possible, then there is no need to verify
the register defaults' stride and the other code followed.
Signed-off-by: NXiubo Li <lixiubo@cmss.chinamobile.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

drivers/base/regmap/regcache.c

@@ -109,6 +109,12 @@ int regcache_init(struct regmap *map, const struct regmap_config *config)
 		return 0;
 	}
 
+	if (config->reg_defaults && !config->num_reg_defaults) {
+		dev_err(map->dev,
+			 "Register defaults are set without the number!\n");
+		return -EINVAL;
+	}
+
 	for (i = 0; i < config->num_reg_defaults; i++)
 		if (config->reg_defaults[i].reg % map->reg_stride)
 			return -EINVAL;
@@ -142,8 +148,6 @@ int regcache_init(struct regmap *map, const struct regmap_config *config)
 	 * a copy of it.
 	 */
 	if (config->reg_defaults) {
-		if (!map->num_reg_defaults)
-			return -EINVAL;
 		tmp_buf = kmemdup(config->reg_defaults, map->num_reg_defaults *
 				  sizeof(struct reg_default), GFP_KERNEL);
 		if (!tmp_buf)