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/openrd_client_defconfig b/configs/openrd_client_defconfig
index 3e6eb17..db1df94 100644
--- a/configs/openrd_client_defconfig
+++ b/configs/openrd_client_defconfig
@@ -24,6 +24,7 @@
 CONFIG_LOGLEVEL=2
 # CONFIG_DISPLAY_BOARDINFO is not set
 CONFIG_RESET_PHY_R=y
+CONFIG_SYS_MAXARGS=32
 # CONFIG_CMD_FLASH is not set
 CONFIG_CMD_IDE=y
 CONFIG_CMD_MMC=y