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/phycore-am335x-r2-wega_defconfig b/configs/phycore-am335x-r2-wega_defconfig
index 45ded51..59a4ef1 100644
--- a/configs/phycore-am335x-r2-wega_defconfig
+++ b/configs/phycore-am335x-r2-wega_defconfig
@@ -29,6 +29,7 @@
 CONFIG_SPL_NAND_BASE=y
 CONFIG_SPL_POWER=y
 CONFIG_HUSH_PARSER=y
+CONFIG_SYS_MAXARGS=64
 CONFIG_CMD_BOOTZ=y
 CONFIG_CMD_SPL=y
 # CONFIG_CMD_FLASH is not set