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/phycore_pcl063_defconfig b/configs/phycore_pcl063_defconfig
index 0a05c4b..dbd4a06 100644
--- a/configs/phycore_pcl063_defconfig
+++ b/configs/phycore_pcl063_defconfig
@@ -20,6 +20,7 @@
 CONFIG_BOARD_EARLY_INIT_F=y
 CONFIG_SPL_USB_HOST=y
 CONFIG_SPL_WATCHDOG=y
+CONFIG_SYS_MAXARGS=32
 CONFIG_CMD_MEMTEST=y
 CONFIG_CMD_DM=y
 CONFIG_CMD_GPIO=y