gpio: ge: Fix build warning

Casting a pointer to u16 can produce a compiler warning such as this:

    drivers/gpio/gpio-ge.c: In function 'gef_gpio_probe':
    drivers/gpio/gpio-ge.c:83:14: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
        gc->ngpio = (u16)of_device_get_match_data(&pdev->dev);
                    ^

Cast the pointer through a uintptr_t to avoid the warning.

Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>