- Add GPIO support for Broadcom Vulcan ARM64.
- Add depends on ARCH_VULCAN to Kconfig to enable gpio controller
  driver for Broadcom Vulcan ARM64 SoCs.
Signed-off-by: Kamlakant Patel <kamlakant.patel@broadcom.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>