microblaze: Added Kconfig support for CONFIG_XILINX_GPIO

This patch added Kconfig support for CONFIG_XILINX_GPIO
and enabled it in respective defconfig.

Signed-off-by: Vipul Kumar <vipulk@xilinx.com>
Signed-off-by: Siva Durga Prasad Paladugu <sivadur@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/configs/microblaze-generic_defconfig b/configs/microblaze-generic_defconfig
index ac49404..699dc44 100644
--- a/configs/microblaze-generic_defconfig
+++ b/configs/microblaze-generic_defconfig
@@ -46,6 +46,7 @@
 CONFIG_BOOTP_GATEWAY=y
 CONFIG_BOOTP_HOSTNAME=y
 CONFIG_SPL_DM=y
+CONFIG_XILINX_GPIO=y
 CONFIG_MTD_NOR_FLASH=y
 CONFIG_PHY_ATHEROS=y
 CONFIG_PHY_BROADCOM=y