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/ls1088aqds_defconfig b/configs/ls1088aqds_defconfig
index d1a6dc5..c3990d6 100644
--- a/configs/ls1088aqds_defconfig
+++ b/configs/ls1088aqds_defconfig
@@ -35,6 +35,7 @@
 CONFIG_DISPLAY_BOARDINFO_LATE=y
 CONFIG_RESET_PHY_R=y
 CONFIG_HUSH_PARSER=y
+CONFIG_SYS_MAXARGS=64
 CONFIG_CMD_GREPENV=y
 CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS=5
 CONFIG_CMD_MEMINFO=y