pinctrl: convert to use match_string() helper

The new helper returns index of the mathing string in an array.  We
would use it here.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/pinctrl/pinmux.c

@@ -334,7 +334,6 @@ int pinmux_map_to_setting(struct pinctrl_map const *map,
 	unsigned num_groups;
 	int ret;
 	const char *group;
-	int i;
 
 	if (!pmxops) {
 		dev_err(pctldev->dev, "does not support mux function\n");
@@ -363,19 +362,13 @@ int pinmux_map_to_setting(struct pinctrl_map const *map,
 		return -EINVAL;
 	}
 	if (map->data.mux.group) {
-		bool found = false;
 		group = map->data.mux.group;
-		for (i = 0; i < num_groups; i++) {
-			if (!strcmp(group, groups[i])) {
-				found = true;
-				break;
-			}
-		}
-		if (!found) {
+		ret = match_string(groups, num_groups, group);
+		if (ret < 0) {
 			dev_err(pctldev->dev,
 				"invalid group \"%s\" for function \"%s\"\n",
 				group, map->data.mux.function);
-			return -EINVAL;
+			return ret;
 		}
 	} else {
 		group = groups[0];