regmap: cache: use kmalloc_array instead of kmalloc

This patch fixes checkpatch.pl warning for regmap cache.
WARNING : prefer kmalloc_array over kmalloc with multiply
Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/base/regmap/regcache.c

@@ -61,8 +61,8 @@ static int regcache_hw_init(struct regmap *map)
 		if (!regmap_volatile(map, i * map->reg_stride))
 			count++;
 
-	map->reg_defaults = kmalloc(count * sizeof(struct reg_default),
-				      GFP_KERNEL);
+	map->reg_defaults = kmalloc_array(count, sizeof(struct reg_default),
+					  GFP_KERNEL);
 	if (!map->reg_defaults) {
 		ret = -ENOMEM;
 		goto err_free;