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/zipitz2_defconfig b/configs/zipitz2_defconfig
index 6da257c..1567aab 100644
--- a/configs/zipitz2_defconfig
+++ b/configs/zipitz2_defconfig
@@ -1,6 +1,8 @@
 CONFIG_ARM=y
 CONFIG_TARGET_ZIPITZ2=y
 CONFIG_ENV_IS_IN_FLASH=y
+CONFIG_USE_BOOTARGS=y
+CONFIG_BOOTARGS="console=tty0 console=ttyS2,115200 fbcon=rotate:3"
 # CONFIG_CONSOLE_MUX is not set
 # CONFIG_DISPLAY_BOARDINFO is not set
 CONFIG_HUSH_PARSER=y