common, kconfig: move VERSION_VARIABLE to Kconfig

move VERSION_VARIABLE from board config file into a
Kconfig option.

Signed-off-by: Heiko Schocher <hs@denx.de>
diff --git a/configs/3c120_defconfig b/configs/3c120_defconfig
index b19c956..dc0d74a 100644
--- a/configs/3c120_defconfig
+++ b/configs/3c120_defconfig
@@ -1,10 +1,9 @@
 CONFIG_NIOS2=y
 CONFIG_SYS_CONFIG_NAME="3c120_devboard"
-CONFIG_DM_SERIAL=y
-CONFIG_DM_GPIO=y
 CONFIG_DEFAULT_DEVICE_TREE="3c120_devboard"
 CONFIG_FIT=y
 CONFIG_OF_BOARD_SETUP=y
+CONFIG_VERSION_VARIABLE=y
 CONFIG_HUSH_PARSER=y
 # CONFIG_AUTOBOOT is not set
 CONFIG_CMD_CPU=y
@@ -19,6 +18,7 @@
 CONFIG_CMD_MII=y
 CONFIG_CMD_PING=y
 CONFIG_NET_RANDOM_ETHADDR=y
+CONFIG_DM_GPIO=y
 CONFIG_ALTERA_PIO=y
 CONFIG_MISC=y
 CONFIG_ALTERA_SYSID=y
@@ -26,6 +26,7 @@
 CONFIG_CFI_FLASH=y
 CONFIG_DM_ETH=y
 CONFIG_ALTERA_TSE=y
+CONFIG_DM_SERIAL=y
 CONFIG_ALTERA_JTAG_UART=y
 CONFIG_ALTERA_JTAG_UART_BYPASS=y
 CONFIG_TIMER=y