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/mpc8308_p1m_defconfig b/configs/mpc8308_p1m_defconfig
index 2c20186..ea67fbe 100644
--- a/configs/mpc8308_p1m_defconfig
+++ b/configs/mpc8308_p1m_defconfig
@@ -1,4 +1,5 @@
 CONFIG_PPC=y
+CONFIG_SYS_TEXT_BASE=0xFC000000
 CONFIG_MPC83xx=y
 CONFIG_TARGET_MPC8308_P1M=y
 CONFIG_OF_BOARD_SETUP=y