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/bcm96753ref_ram_defconfig b/configs/bcm96753ref_ram_defconfig
index 9a72c75..ca3ac5b 100644
--- a/configs/bcm96753ref_ram_defconfig
+++ b/configs/bcm96753ref_ram_defconfig
@@ -23,6 +23,7 @@
 # CONFIG_AUTOBOOT is not set
 CONFIG_SYS_CONSOLE_IS_IN_ENV=y
 CONFIG_HUSH_PARSER=y
+CONFIG_SYS_MAXARGS=24
 # CONFIG_CMD_BOOTD is not set
 # CONFIG_BOOTM_NETBSD is not set
 # CONFIG_BOOTM_PLAN9 is not set