Convert CONFIG_SPL_BSS_START_ADDR to Kconfig

This converts the following to Kconfig:
   CONFIG_SPL_BSS_START_ADDR

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/r8a77970_eagle_defconfig b/configs/r8a77970_eagle_defconfig
index dfb4adf..9ca3ddf 100644
--- a/configs/r8a77970_eagle_defconfig
+++ b/configs/r8a77970_eagle_defconfig
@@ -22,6 +22,8 @@
 CONFIG_BOOTCOMMAND="tftp 0x48080000 Image; tftp 0x48000000 Image-r8a77970-eagle.dtb; booti 0x48080000 - 0x48000000"
 CONFIG_DEFAULT_FDT_FILE="r8a77970-eagle.dtb"
 CONFIG_SYS_MALLOC_BOOTPARAMS=y
+CONFIG_SPL_HAS_BSS_LINKER_SECTION=y
+CONFIG_SPL_BSS_START_ADDR=0xe631f000
 CONFIG_SPL_BSS_MAX_SIZE=0x1000
 # CONFIG_SPL_SHARES_INIT_SP_ADDR is not set
 CONFIG_SPL_STACK=0xe6304000