gpio/xilinx: Add support for X86 Arch

Core can be accessed via PCIe on X86 platform.
This patch also allows the driver to be used as module.

Acked-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index cb235f3..1eff81c 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -367,8 +367,8 @@
 	  here to enable the GFC GPIO functionality.
 
 config GPIO_XILINX
-	bool "Xilinx GPIO support"
-	depends on PPC_OF || MICROBLAZE || ARCH_ZYNQ
+	tristate "Xilinx GPIO support"
+	depends on OF_GPIO && (PPC_OF || MICROBLAZE || ARCH_ZYNQ || ARCH_X86)
 	help
 	  Say yes here to support the Xilinx FPGA GPIO device