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/ci20_mmc_defconfig b/configs/ci20_mmc_defconfig
index a533706..4d963c3 100644
--- a/configs/ci20_mmc_defconfig
+++ b/configs/ci20_mmc_defconfig
@@ -22,6 +22,7 @@
 CONFIG_DISPLAY_CPUINFO=y
 CONFIG_BOARD_EARLY_INIT_F=y
 CONFIG_MISC_INIT_R=y
+CONFIG_SYS_MALLOC_BOOTPARAMS=y
 # CONFIG_SPL_BANNER_PRINT is not set
 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_USE_SECTOR=y
 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR=0x1c