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/M53017EVB_defconfig b/configs/M53017EVB_defconfig
index 45656a3..246bc8a 100644
--- a/configs/M53017EVB_defconfig
+++ b/configs/M53017EVB_defconfig
@@ -13,6 +13,7 @@
 CONFIG_USE_BOOTARGS=y
 CONFIG_BOOTARGS="root=/dev/mtdblock3 rw rootfstype=jffs2"
 # 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="-> "