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/puma-rk3399_defconfig b/configs/puma-rk3399_defconfig
index e859172..f902f14 100644
--- a/configs/puma-rk3399_defconfig
+++ b/configs/puma-rk3399_defconfig
@@ -24,6 +24,8 @@
 CONFIG_MISC_INIT_R=y
 CONFIG_SPL_MAX_SIZE=0x2e000
 CONFIG_SPL_PAD_TO=0x7f8000
+CONFIG_SPL_HAS_BSS_LINKER_SECTION=y
+CONFIG_SPL_BSS_START_ADDR=0xff8e0000
 CONFIG_SPL_BSS_MAX_SIZE=0x10000
 # CONFIG_SPL_RAW_IMAGE_SUPPORT is not set
 # CONFIG_SPL_SHARES_INIT_SP_ADDR is not set