gpio: merrifield: Make bias configuration available for GPIOs

If we get bias set request, for example, from GpioIo() resource,
we silently ignore it. Make bias configuration available for GPIOs.

Signed-off-by: Andy Shevchenko <[e-mail]>

drivers/gpio/gpio-merrifield.c

···
 {
 	u32 debounce;
 
+	if ((pinconf_to_config_param(config) == PIN_CONFIG_BIAS_DISABLE) ||
+	    (pinconf_to_config_param(config) == PIN_CONFIG_BIAS_PULL_UP) ||
+	    (pinconf_to_config_param(config) == PIN_CONFIG_BIAS_PULL_DOWN))
+		return gpiochip_generic_config(chip, offset, config);
+
 	if (pinconf_to_config_param(config) != PIN_CONFIG_INPUT_DEBOUNCE)
 		return -ENOTSUPP;