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/ls1046ardb_qspi_spl_defconfig b/configs/ls1046ardb_qspi_spl_defconfig
index 9d43c35..b32319d 100644
--- a/configs/ls1046ardb_qspi_spl_defconfig
+++ b/configs/ls1046ardb_qspi_spl_defconfig
@@ -48,6 +48,7 @@
 CONFIG_SPL_OS_BOOT=y
 CONFIG_SYS_OS_BASE=0x40980000
 CONFIG_SPL_WATCHDOG=y
+CONFIG_SYS_MAXARGS=64
 CONFIG_CMD_SPL=y
 CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS=5
 CONFIG_CMD_DM=y