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/ls1043ardb_defconfig b/configs/ls1043ardb_defconfig
index c617716..c068892 100644
--- a/configs/ls1043ardb_defconfig
+++ b/configs/ls1043ardb_defconfig
@@ -25,6 +25,7 @@
 CONFIG_BOOTCOMMAND="run distro_bootcmd; run nor_bootcmd; env exists secureboot && esbc_halt;"
 CONFIG_ARCH_MISC_INIT=y
 CONFIG_MISC_INIT_R=y
+CONFIG_SYS_MAXARGS=64
 CONFIG_CMD_IMLS=y
 CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS=5
 CONFIG_CMD_DM=y