gpio: serial: max310x: Use HW type for gpio_chip's label

Some debugging tools (/sys/kernel/debug/gpio, `lsgpio`) use the
gpio_chip's label for displaying an additional context. Right now, the
information duplicates stuff which is already available from the
parent's device. This is how e.g. `lsgpio`'s output looks like:

  GPIO chip: gpiochip2, "spi1.2", 16 GPIO lines

Comparing the output of other GPIO expanders that I have available:

  gpiochip4: GPIOs 464-479, parent: spi/spi1.1, mcp23s17, can sleep:
  gpiochip5: GPIOs 448-463, parent: i2c/0-0020, pca9555, can sleep:
  gpiochip2: GPIOs 496-511, parent: spi/spi1.2, spi1.2, can sleep:

This patch ensures that the type of the real HW device is shown instead
of duplicating the SPI path:

  gpiochip2: GPIOs 496-511, parent: spi/spi1.2, MAX14830, can sleep:
Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/max310x.c

@@ -1318,7 +1318,7 @@ static int max310x_probe(struct device *dev, struct max310x_devtype *devtype,
 	/* Setup GPIO cotroller */
 	s->gpio.owner		= THIS_MODULE;
 	s->gpio.parent		= dev;
-	s->gpio.label		= dev_name(dev);
+	s->gpio.label		= devtype->name;
 	s->gpio.direction_input	= max310x_gpio_direction_input;
 	s->gpio.get		= max310x_gpio_get;
 	s->gpio.direction_output= max310x_gpio_direction_output;