common: Move CONFIG_BOOTARGS to Kconfig

Also introduce CONFIG_USE_BOOTARGS option so we can control if
CONFIG_BOOTARGS defined at all.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
[trini: Resync r8a779[56]_ulcb, various ls10xx targets]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/s32v234evb_defconfig b/configs/s32v234evb_defconfig
index be4b716..e227152 100644
--- a/configs/s32v234evb_defconfig
+++ b/configs/s32v234evb_defconfig
@@ -4,6 +4,8 @@
 CONFIG_SYS_MALLOC_F=y
 CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=board/freescale/s32v234evb/s32v234evb.cfg"
 CONFIG_ENV_IS_IN_MMC=y
+CONFIG_USE_BOOTARGS=y
+CONFIG_BOOTARGS="console=ttyLF0 root=/dev/ram rw"
 CONFIG_BOARD_EARLY_INIT_F=y
 CONFIG_CMD_BOOTZ=y
 CONFIG_OF_LIBFDT=y