regmap: Make return code checks consistent

The range code was written to check for return codes less than zero as
errors but throughout the rest of the API return codes not equal to zero
are errors. Change all these checks to match the house style.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

drivers/base/regmap/regmap.c

@@ -606,7 +606,7 @@ struct regmap *regmap_init(struct device *dev,
 	}
 
 	ret = regcache_init(map, config);
-	if (ret < 0)
+	if (ret != 0)
 		goto err_range;
 
 	regmap_debugfs_init(map, config->name);
@@ -803,7 +803,7 @@ static int _regmap_select_page(struct regmap *map, unsigned int *reg,
 
 		map->work_buf = orig_work_buf;
 
-		if (ret < 0)
+		if (ret != 0)
 			return ret;
 	}
 
@@ -854,7 +854,7 @@ static int _regmap_raw_write(struct regmap *map, unsigned int reg,
 	if (range) {
 		ret = _regmap_select_page(map, &reg, range,
 					  val_len / map->format.val_bytes);
-		if (ret < 0)
+		if (ret != 0)
 			return ret;
 	}
 
@@ -930,7 +930,7 @@ int _regmap_write(struct regmap *map, unsigned int reg,
 		range = _regmap_range_lookup(map, reg);
 		if (range) {
 			ret = _regmap_select_page(map, &reg, range, 1);
-			if (ret < 0)
+			if (ret != 0)
 				return ret;
 		}
 
@@ -1096,7 +1096,7 @@ static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 	if (range) {
 		ret = _regmap_select_page(map, &reg, range,
 					  val_len / map->format.val_bytes);
-		if (ret < 0)
+		if (ret != 0)
 			return ret;
 	}