usb: common: 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: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/usb/common/common.c

@@ -64,18 +64,15 @@ EXPORT_SYMBOL_GPL(usb_speed_string);
 enum usb_device_speed usb_get_maximum_speed(struct device *dev)
 {
 	const char *maximum_speed;
-	int err;
-	int i;
+	int ret;
 
-	err = device_property_read_string(dev, "maximum-speed", &maximum_speed);
-	if (err < 0)
+	ret = device_property_read_string(dev, "maximum-speed", &maximum_speed);
+	if (ret < 0)
 		return USB_SPEED_UNKNOWN;
 
-	for (i = 0; i < ARRAY_SIZE(speed_names); i++)
-		if (strcmp(maximum_speed, speed_names[i]) == 0)
-			return i;
+	ret = match_string(speed_names, ARRAY_SIZE(speed_names), maximum_speed);
 
-	return USB_SPEED_UNKNOWN;
+	return (ret < 0) ? USB_SPEED_UNKNOWN : ret;
 }
 EXPORT_SYMBOL_GPL(usb_get_maximum_speed);
 
@@ -109,13 +106,10 @@ static const char *const usb_dr_modes[] = {
 
 static enum usb_dr_mode usb_get_dr_mode_from_string(const char *str)
 {
-	int i;
-
-	for (i = 0; i < ARRAY_SIZE(usb_dr_modes); i++)
-		if (!strcmp(usb_dr_modes[i], str))
-			return i;
+	int ret;
 
-	return USB_DR_MODE_UNKNOWN;
+	ret = match_string(usb_dr_modes, ARRAY_SIZE(usb_dr_modes), str);
+	return (ret < 0) ? USB_DR_MODE_UNKNOWN : ret;
 }
 
 enum usb_dr_mode usb_get_dr_mode(struct device *dev)