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/m53menlo_defconfig b/configs/m53menlo_defconfig
index 90d3e59..cfaa0e1 100644
--- a/configs/m53menlo_defconfig
+++ b/configs/m53menlo_defconfig
@@ -34,6 +34,7 @@
 CONFIG_SPL_BOARD_INIT=y
 CONFIG_SPL_NAND_SUPPORT=y
 CONFIG_HUSH_PARSER=y
+CONFIG_SYS_MAXARGS=32
 CONFIG_CMD_ASKENV=y
 CONFIG_CMD_GREPENV=y
 CONFIG_CMD_DM=y