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/vinco_defconfig b/configs/vinco_defconfig
index cb2040e..f61ad4a 100644
--- a/configs/vinco_defconfig
+++ b/configs/vinco_defconfig
@@ -4,6 +4,8 @@
 CONFIG_SYS_EXTRA_OPTIONS="SAMA5D4,SYS_USE_SERIALFLASH"
 CONFIG_ENV_IS_IN_SPI_FLASH=y
 CONFIG_BOOTDELAY=3
+CONFIG_USE_BOOTARGS=y
+CONFIG_BOOTARGS="console=ttyS0,115200 earlyprintk rw root=/dev/mmcblk0p2 rootfstype=ext4 rootwait quiet lpj=1990656"
 # CONFIG_DISPLAY_BOARDINFO is not set
 CONFIG_BOARD_EARLY_INIT_F=y
 CONFIG_HUSH_PARSER=y