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/thunderx_88xx_defconfig b/configs/thunderx_88xx_defconfig
index 2c7a5a6..7e7cd8e 100644
--- a/configs/thunderx_88xx_defconfig
+++ b/configs/thunderx_88xx_defconfig
@@ -5,6 +5,8 @@
 CONFIG_DEBUG_UART=y
 CONFIG_ENV_IS_NOWHERE=y
 CONFIG_BOOTDELAY=5
+CONFIG_USE_BOOTARGS=y
+CONFIG_BOOTARGS="console=ttyAMA0,115200n8 earlycon=pl011,0x87e024000000 debug maxcpus=48 rootwait rw root=/dev/sda2 coherent_pool=16M"
 # CONFIG_DISPLAY_CPUINFO is not set
 # CONFIG_DISPLAY_BOARDINFO is not set
 CONFIG_HUSH_PARSER=y