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/maxbcm_defconfig b/configs/maxbcm_defconfig
index c325dd7..4e9ec52 100644
--- a/configs/maxbcm_defconfig
+++ b/configs/maxbcm_defconfig
@@ -23,6 +23,7 @@
 # CONFIG_DISPLAY_BOARDINFO is not set
 CONFIG_DISPLAY_BOARDINFO_LATE=y
 CONFIG_SPL_I2C=y
+CONFIG_SYS_MAXARGS=32
 CONFIG_CMD_I2C=y
 CONFIG_CMD_SPI=y
 # CONFIG_CMD_SETEXPR is not set