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/synquacer_developerbox_defconfig b/configs/synquacer_developerbox_defconfig
index add6041..d897eaf 100644
--- a/configs/synquacer_developerbox_defconfig
+++ b/configs/synquacer_developerbox_defconfig
@@ -14,6 +14,7 @@
 CONFIG_FIT=y
 CONFIG_BOOTSTAGE_STASH_SIZE=4096
 CONFIG_HUSH_PARSER=y
+CONFIG_SYS_MAXARGS=128
 CONFIG_CMD_IMLS=y
 CONFIG_CMD_ERASEENV=y
 CONFIG_CMD_NVEDIT_EFI=y