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/gwventana_nand_defconfig b/configs/gwventana_nand_defconfig
index 8ef794c..16e94bc 100644
--- a/configs/gwventana_nand_defconfig
+++ b/configs/gwventana_nand_defconfig
@@ -51,6 +51,7 @@
 CONFIG_SPL_POWER=y
 CONFIG_HUSH_PARSER=y
 CONFIG_SYS_PROMPT="Ventana > "
+CONFIG_SYS_MAXARGS=32
 CONFIG_CMD_BOOTZ=y
 CONFIG_CMD_SPL_NAND_OFS=0x1100000
 CONFIG_CMD_SPL_WRITE_SIZE=0x20000