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/cm_t335_defconfig b/configs/cm_t335_defconfig
index 0b4912b..556035f 100644
--- a/configs/cm_t335_defconfig
+++ b/configs/cm_t335_defconfig
@@ -27,6 +27,7 @@
 CONFIG_SPL_WATCHDOG=y
 # CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC is not set
 CONFIG_SYS_PROMPT="CM-T335 # "
+CONFIG_SYS_MAXARGS=64
 CONFIG_CMD_ASKENV=y
 CONFIG_CMD_EEPROM=y
 CONFIG_CMD_EEPROM_LAYOUT=y