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/ls1012afrwy_tfa_defconfig b/configs/ls1012afrwy_tfa_defconfig
index 4d718cd..7d892a3 100644
--- a/configs/ls1012afrwy_tfa_defconfig
+++ b/configs/ls1012afrwy_tfa_defconfig
@@ -25,6 +25,7 @@
 CONFIG_BOOTARGS="console=ttyS0,115200 root=/dev/ram0 earlycon=uart8250,mmio,0x21c0500 quiet lpj=250000"
 # CONFIG_DISPLAY_BOARDINFO is not set
 CONFIG_DISPLAY_BOARDINFO_LATE=y
+CONFIG_SYS_MAXARGS=64
 CONFIG_CMD_GREPENV=y
 CONFIG_CMD_MEMINFO=y
 CONFIG_CMD_MEMTEST=y