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/libretech-s905d-pc_defconfig b/configs/libretech-s905d-pc_defconfig
index 8ee69ca..a9c0a5f 100644
--- a/configs/libretech-s905d-pc_defconfig
+++ b/configs/libretech-s905d-pc_defconfig
@@ -19,6 +19,7 @@
 CONFIG_USE_PREBOOT=y
 # CONFIG_DISPLAY_CPUINFO is not set
 CONFIG_MISC_INIT_R=y
+CONFIG_SYS_MAXARGS=32
 # CONFIG_CMD_BDI is not set
 # CONFIG_CMD_IMI is not set
 CONFIG_CMD_ADC=y