gpio: regmap: use new regmap_might_sleep()

Now that the regmap can be queried whether it might sleep, we can get
rid of the conservative setting "can_sleep = true". New drivers which
want to use gpio-regmap and can access the registers memory-mapped won't
have the restriction that their consumers have to use the
gpiod_*cansleep() variants anymore.
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

drivers/gpio/gpio-regmap.c

@@ -254,15 +254,7 @@ struct gpio_regmap *gpio_regmap_register(const struct gpio_regmap_config *config
 	chip->ngpio = config->ngpio;
 	chip->names = config->names;
 	chip->label = config->label ?: dev_name(config->parent);
-
-	/*
-	 * If our regmap is fast_io we should probably set can_sleep to false.
-	 * Right now, the regmap doesn't save this property, nor is there any
-	 * access function for it.
-	 * The only regmap type which uses fast_io is regmap-mmio. For now,
-	 * assume a safe default of true here.
-	 */
-	chip->can_sleep = true;
+	chip->can_sleep = regmap_might_sleep(config->regmap);
 
 	chip->get = gpio_regmap_get;
 	if (gpio->reg_set_base && gpio->reg_clr_base)