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/da850evm_defconfig b/configs/da850evm_defconfig
index a4bc7e4..d150a00 100644
--- a/configs/da850evm_defconfig
+++ b/configs/da850evm_defconfig
@@ -36,6 +36,8 @@
 CONFIG_CLOCKS=y
 CONFIG_MISC_INIT_R=y
 CONFIG_SPL_PAD_TO=0x8000
+CONFIG_SPL_HAS_BSS_LINKER_SECTION=y
+CONFIG_SPL_BSS_START_ADDR=0xc0000000
 CONFIG_SPL_FOOTPRINT_LIMIT=y
 CONFIG_SPL_MAX_FOOTPRINT=0x8000
 CONFIG_SPL_SYS_MALLOC_SIMPLE=y