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/Ampe_A76_defconfig b/configs/Ampe_A76_defconfig
index 2a12595..ebfc7e0 100644
--- a/configs/Ampe_A76_defconfig
+++ b/configs/Ampe_A76_defconfig
@@ -1,5 +1,6 @@
 CONFIG_ARM=y
 CONFIG_ARCH_SUNXI=y
+CONFIG_SYS_TEXT_BASE=0x4a000000
 CONFIG_MACH_SUN5I=y
 CONFIG_DRAM_CLK=432
 CONFIG_MMC0_CD_PIN="PG0"