configs: Migrate CONFIG_SYS_TEXT_BASE

On the NIOS2 and Xtensa architectures, we do not have
CONFIG_SYS_TEXT_BASE set.  This is a strict migration of the current
values into the defconfig and removing them from the headers.

I did not attempt to add more default values in and for now will leave
that to maintainers.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/stm32f469-discovery_defconfig b/configs/stm32f469-discovery_defconfig
index 8190b82..960ce10 100644
--- a/configs/stm32f469-discovery_defconfig
+++ b/configs/stm32f469-discovery_defconfig
@@ -1,5 +1,6 @@
 CONFIG_ARM=y
 CONFIG_STM32=y
+CONFIG_SYS_TEXT_BASE=0x08000000
 CONFIG_SYS_MALLOC_F_LEN=0xF00
 CONFIG_STM32F4=y
 CONFIG_TARGET_STM32F469_DISCOVERY=y