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/mx53ppd_defconfig b/configs/mx53ppd_defconfig
index e4eddef..77551cd 100644
--- a/configs/mx53ppd_defconfig
+++ b/configs/mx53ppd_defconfig
@@ -22,6 +22,7 @@
 CONFIG_BOARD_LATE_INIT=y
 CONFIG_MISC_INIT_R=y
 CONFIG_HUSH_PARSER=y
+CONFIG_SYS_MAXARGS=48
 CONFIG_CMD_BOOTZ=y
 CONFIG_CMD_DM=y
 CONFIG_CMD_FUSE=y