nios2: Enable support for fitImage

The uImage format is legacy for years now, enable support for the
fitImage format, which allows combining multiple files (kernel and
dtb) into a single file, offers better protection of the payload
and so on.
Signed-off-by: NMarek Vasut <marex@denx.de>
Signed-off-by: NThomas Chou <thomas@wytron.com.tw>

configs/10m50_defconfig

@@ -3,6 +3,7 @@ CONFIG_SYS_CONFIG_NAME="10m50_devboard"
 CONFIG_DM_SERIAL=y
 CONFIG_DM_GPIO=y
 CONFIG_DEFAULT_DEVICE_TREE="10m50_devboard"
+CONFIG_FIT=y
 CONFIG_HUSH_PARSER=y
 CONFIG_CMD_CPU=y
 # CONFIG_CMD_BOOTD is not set

configs/3c120_defconfig

@@ -3,6 +3,7 @@ CONFIG_SYS_CONFIG_NAME="3c120_devboard"
 CONFIG_DM_SERIAL=y
 CONFIG_DM_GPIO=y
 CONFIG_DEFAULT_DEVICE_TREE="3c120_devboard"
+CONFIG_FIT=y
 CONFIG_HUSH_PARSER=y
 CONFIG_CMD_CPU=y
 # CONFIG_CMD_BOOTD is not set