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/ls2088aqds_tfa_defconfig b/configs/ls2088aqds_tfa_defconfig
index cd535ba..11d7a51 100644
--- a/configs/ls2088aqds_tfa_defconfig
+++ b/configs/ls2088aqds_tfa_defconfig
@@ -29,6 +29,7 @@
 CONFIG_USE_BOOTARGS=y
 CONFIG_BOOTARGS="console=ttyS0,115200 root=/dev/ram0 earlycon=uart8250,mmio,0x21c0500 ramdisk_size=0x2000000 default_hugepagesz=2m hugepagesz=2m hugepages=256"
 CONFIG_RESET_PHY_R=y
+CONFIG_SYS_MAXARGS=64
 CONFIG_CMD_IMLS=y
 CONFIG_CMD_GREPENV=y
 CONFIG_CMD_EEPROM=y