Convert CONFIG_SYS_DEVICE_NULLDEV to Kconfig
This converts the following to Kconfig:
CONFIG_SYS_DEVICE_NULLDEV
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/M5249EVB_defconfig b/configs/M5249EVB_defconfig
index d4871c6..8f8a4a6 100644
--- a/configs/M5249EVB_defconfig
+++ b/configs/M5249EVB_defconfig
@@ -5,6 +5,7 @@
CONFIG_TARGET_M5249EVB=y
CONFIG_DEFAULT_DEVICE_TREE="M5249EVB"
CONFIG_SYS_CONSOLE_INFO_QUIET=y
+CONFIG_SYS_DEVICE_NULLDEV=y
# CONFIG_DISPLAY_BOARDINFO is not set
# CONFIG_CMDLINE_EDITING is not set
# CONFIG_AUTOBOOT is not set