Convert CONFIG_SYS_BOOTPARAMS_LEN to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_BOOTPARAMS_LEN

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/M5208EVBE_defconfig b/configs/M5208EVBE_defconfig
index df4da88..757792f 100644
--- a/configs/M5208EVBE_defconfig
+++ b/configs/M5208EVBE_defconfig
@@ -11,6 +11,7 @@
 CONFIG_SYS_MONITOR_BASE=0x00000400
 CONFIG_BOOTDELAY=1
 # CONFIG_DISPLAY_BOARDINFO is not set
+CONFIG_SYS_MALLOC_BOOTPARAMS=y
 # CONFIG_CMDLINE_EDITING is not set
 # CONFIG_AUTO_COMPLETE is not set
 CONFIG_SYS_PROMPT="-> "