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/s5p_goni_defconfig b/configs/s5p_goni_defconfig
index 8bfab75..999342d 100644
--- a/configs/s5p_goni_defconfig
+++ b/configs/s5p_goni_defconfig
@@ -3,6 +3,8 @@
 CONFIG_TARGET_S5P_GONI=y
 CONFIG_DEFAULT_DEVICE_TREE="s5pc1xx-goni"
 CONFIG_ENV_IS_IN_MMC=y
+CONFIG_USE_BOOTARGS=y
+CONFIG_BOOTARGS="root=/dev/mtdblock8 rootfstype=ext4 ${console} ${meminfo} ${mtdparts}"
 CONFIG_SYS_CONSOLE_IS_IN_ENV=y
 CONFIG_HUSH_PARSER=y
 CONFIG_SYS_PROMPT="Goni # "