gpio: 74xx: Fix build warning about void to integer cast

This fixes the build warning , warning: cast from pointer to integer
of different size when building this file on a x86 allmodconfig
configuration. In order for me to fix this build warning I changed
the cast in the function mmio_74xx_gpio_probe from casting the
variable data of the stucture pointer of_id to uintptr_t rather
then unsigned when assigning to the variable flag of the structure
pointer priv of the structure type mmio_74xx_gpio_priv.
Signed-off-by: Nicholas Krause <xerofoify@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-74xx-mmio.c

@@ -129,7 +129,7 @@ static int mmio_74xx_gpio_probe(struct platform_device *pdev)
 	if (IS_ERR(dat))
 		return PTR_ERR(dat);
 
-	priv->flags = (unsigned)of_id->data;
+	priv->flags = (uintptr_t) of_id->data;
 
 	err = bgpio_init(&priv->bgc, &pdev->dev,
 			 DIV_ROUND_UP(MMIO_74XX_BIT_CNT(priv->flags), 8),