gpio: mxc: read output value from GPIO_DR register

All supported iMX GPIO controllers store configured GPIO output value
in GPIO_DR data register, which is represented by GPIO generic reg_set.
Provide a BGPIOF_READ_OUTPUT_REG_SET flag to bgpio_init() to allow
correct getting of previously set output value.

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-mxc.c

@@ -450,7 +450,8 @@ static int mxc_gpio_probe(struct platform_device *pdev)
 	err = bgpio_init(&port->bgc, &pdev->dev, 4,
 			 port->base + GPIO_PSR,
 			 port->base + GPIO_DR, NULL,
-			 port->base + GPIO_GDIR, NULL, 0);
+			 port->base + GPIO_GDIR, NULL,
+			 BGPIOF_READ_OUTPUT_REG_SET);
 	if (err)
 		goto out_bgio;