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/vocore2_defconfig b/configs/vocore2_defconfig
index ff7a0dd..33d27ad 100644
--- a/configs/vocore2_defconfig
+++ b/configs/vocore2_defconfig
@@ -30,6 +30,7 @@
 CONFIG_LOGLEVEL=8
 # CONFIG_DISPLAY_BOARDINFO is not set
 CONFIG_DISPLAY_BOARDINFO_LATE=y
+CONFIG_SYS_MALLOC_BOOTPARAMS=y
 CONFIG_SPL_SYS_MALLOC_SIMPLE=y
 CONFIG_SPL_NOR_SUPPORT=y
 CONFIG_HUSH_PARSER=y