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/ls1088aqds_sdcard_ifc_defconfig b/configs/ls1088aqds_sdcard_ifc_defconfig
index 8b03ff8..0cc3d42 100644
--- a/configs/ls1088aqds_sdcard_ifc_defconfig
+++ b/configs/ls1088aqds_sdcard_ifc_defconfig
@@ -42,6 +42,8 @@
 CONFIG_DISPLAY_BOARDINFO_LATE=y
 CONFIG_RESET_PHY_R=y
 CONFIG_SPL_MAX_SIZE=0x16000
+CONFIG_SPL_HAS_BSS_LINKER_SECTION=y
+CONFIG_SPL_BSS_START_ADDR=0x80100000
 CONFIG_SPL_BSS_MAX_SIZE=0x100000
 # CONFIG_SPL_SHARES_INIT_SP_ADDR is not set
 CONFIG_SPL_STACK=0x18009ff0