gpio: dwapb: Add ACPI device ID for DWAPB GPIO controller on X-Gene platforms

This patch enables DWAPB GPIO controller support on X-Gene
platforms in ACPI boot mode.

Signed-off-by: Duc Dang <dhdang@apm.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>