gpio: da8xx_gpio: Fix compiler warning

Fix below compiler warning for 64bit builds

drivers/gpio/da8xx_gpio.c: In function ‘davinci_get_gpio_bank’:
drivers/gpio/da8xx_gpio.c:446:9: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
  return (struct davinci_gpio *)addr;

Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Signed-off-by: Faiz Abbas <faiz_abbas@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>