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/MPC8641HPCN_36BIT_defconfig b/configs/MPC8641HPCN_36BIT_defconfig
index a85ecfb..c333db5 100644
--- a/configs/MPC8641HPCN_36BIT_defconfig
+++ b/configs/MPC8641HPCN_36BIT_defconfig
@@ -1,4 +1,5 @@
 CONFIG_PPC=y
+CONFIG_SYS_TEXT_BASE=0xeff00000
 CONFIG_MPC86xx=y
 CONFIG_TARGET_MPC8641HPCN=y
 CONFIG_PHYS_64BIT=y