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/tplink_wdr4300_defconfig b/configs/tplink_wdr4300_defconfig
index 091124e..ed86488 100644
--- a/configs/tplink_wdr4300_defconfig
+++ b/configs/tplink_wdr4300_defconfig
@@ -1,4 +1,5 @@
 CONFIG_MIPS=y
+CONFIG_SYS_TEXT_BASE=0xA1000000
 CONFIG_SYS_MALLOC_F_LEN=0x2000
 CONFIG_ARCH_ATH79=y
 CONFIG_BOARD_TPLINK_WDR4300=y