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/bubblegum_96_defconfig b/configs/bubblegum_96_defconfig
index a21b245..33402f2 100644
--- a/configs/bubblegum_96_defconfig
+++ b/configs/bubblegum_96_defconfig
@@ -14,6 +14,7 @@
 # CONFIG_DISPLAY_CPUINFO is not set
 # CONFIG_DISPLAY_BOARDINFO is not set
 CONFIG_SYS_PROMPT="U-Boot => "
+CONFIG_SYS_MAXARGS=64
 CONFIG_CMD_MD5SUM=y
 CONFIG_CMD_MEMINFO=y
 CONFIG_CMD_CACHE=y