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/pogo_e02_defconfig b/configs/pogo_e02_defconfig
index 2d807f1..d512fd4 100644
--- a/configs/pogo_e02_defconfig
+++ b/configs/pogo_e02_defconfig
@@ -20,6 +20,7 @@
 CONFIG_USE_PREBOOT=y
 # CONFIG_DISPLAY_BOARDINFO is not set
 CONFIG_SYS_PROMPT="PogoE02> "
+CONFIG_SYS_MAXARGS=32
 # CONFIG_CMD_FLASH is not set
 CONFIG_CMD_NAND=y
 CONFIG_CMD_USB=y