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/socfpga_secu1_defconfig b/configs/socfpga_secu1_defconfig
index 641d205..2fea52b 100644
--- a/configs/socfpga_secu1_defconfig
+++ b/configs/socfpga_secu1_defconfig
@@ -36,6 +36,7 @@
 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION=0x1
 # CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_USE_PARTITION_TYPE is not set
 CONFIG_SPL_MTD_SUPPORT=y
+CONFIG_SYS_MAXARGS=32
 CONFIG_CMD_ASKENV=y
 CONFIG_CMD_GREPENV=y
 CONFIG_CMD_EEPROM=y