Convert CONFIG_KIRKWOOD_GPIO to Kconfig

This converts the following to Kconfig:
   CONFIG_KIRKWOOD_GPIO

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/kmnusa_defconfig b/configs/kmnusa_defconfig
index 3696572..d81c787 100644
--- a/configs/kmnusa_defconfig
+++ b/configs/kmnusa_defconfig
@@ -53,6 +53,7 @@
 CONFIG_NETCONSOLE=y
 CONFIG_BOOTCOUNT_LIMIT=y
 CONFIG_BOOTCOUNT_RAM=y
+CONFIG_KIRKWOOD_GPIO=y
 CONFIG_SYS_I2C_LEGACY=y
 CONFIG_SYS_I2C_SOFT=y
 CONFIG_SYS_I2C_SOFT_SLAVE=0x0