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/som-db5800-som-6867_defconfig b/configs/som-db5800-som-6867_defconfig
index 538dd2a..ba0f7a3 100644
--- a/configs/som-db5800-som-6867_defconfig
+++ b/configs/som-db5800-som-6867_defconfig
@@ -1,4 +1,5 @@
 CONFIG_X86=y
+CONFIG_SYS_TEXT_BASE=0xFFF00000
 CONFIG_VENDOR_ADVANTECH=y
 CONFIG_TARGET_SOM_DB5800_SOM_6867=y
 CONFIG_DEFAULT_DEVICE_TREE="baytrail_som-db5800-som-6867"