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/mx6sxsabresd_defconfig b/configs/mx6sxsabresd_defconfig
index b5b0b37..911839d 100644
--- a/configs/mx6sxsabresd_defconfig
+++ b/configs/mx6sxsabresd_defconfig
@@ -16,6 +16,7 @@
 CONFIG_BOOTCOMMAND="run findfdt; mmc dev ${mmcdev}; if mmc rescan; then if run loadbootscript; then run bootscript; else if run loadimage; then run mmcboot; else run netboot; fi; fi; else run netboot; fi"
 CONFIG_SYS_CONSOLE_IS_IN_ENV=y
 CONFIG_HUSH_PARSER=y
+CONFIG_SYS_MAXARGS=32
 CONFIG_CMD_BOOTZ=y
 # CONFIG_CMD_FLASH is not set
 CONFIG_CMD_GPIO=y