Convert CONFIG_SYS_MAXARGS to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_MAXARGS

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/opos6uldev_defconfig b/configs/opos6uldev_defconfig
index 5f5cace..b56da14 100644
--- a/configs/opos6uldev_defconfig
+++ b/configs/opos6uldev_defconfig
@@ -36,6 +36,7 @@
 CONFIG_SPL_YMODEM_SUPPORT=y
 CONFIG_HUSH_PARSER=y
 CONFIG_SYS_PROMPT="BIOS> "
+CONFIG_SYS_MAXARGS=32
 CONFIG_CMD_CONFIG=y
 CONFIG_CMD_LICENSE=y
 CONFIG_CMD_BOOTZ=y