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/aristainetos2b_defconfig b/configs/aristainetos2b_defconfig
index fbb2c1c..8d12c4b 100644
--- a/configs/aristainetos2b_defconfig
+++ b/configs/aristainetos2b_defconfig
@@ -1,5 +1,6 @@
 CONFIG_ARM=y
 CONFIG_ARCH_MX6=y
+CONFIG_SYS_TEXT_BASE=0x17800000
 CONFIG_TARGET_ARISTAINETOS2B=y
 CONFIG_FIT=y
 CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=board/aristainetos/aristainetos2.cfg,MX6DL"