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/ds414_defconfig b/configs/ds414_defconfig
index 81a767c..e10b9d2 100644
--- a/configs/ds414_defconfig
+++ b/configs/ds414_defconfig
@@ -32,6 +32,7 @@
 CONFIG_DISPLAY_BOARDINFO_LATE=y
 CONFIG_MISC_INIT_R=y
 CONFIG_SPL_I2C=y
+CONFIG_SYS_MAXARGS=32
 # CONFIG_CMD_FLASH is not set
 CONFIG_CMD_I2C=y
 CONFIG_CMD_PCI=y