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/M5235EVB_Flash32_defconfig b/configs/M5235EVB_Flash32_defconfig
index 5789d89..1ed127c 100644
--- a/configs/M5235EVB_Flash32_defconfig
+++ b/configs/M5235EVB_Flash32_defconfig
@@ -12,6 +12,7 @@
 CONFIG_SYS_MONITOR_BASE=0xFFC00400
 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_PBSIZE=276