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/M54451EVB_stmicro_defconfig b/configs/M54451EVB_stmicro_defconfig
index 715b2c3..79f38db 100644
--- a/configs/M54451EVB_stmicro_defconfig
+++ b/configs/M54451EVB_stmicro_defconfig
@@ -1,5 +1,5 @@
 CONFIG_M68K=y
-CONFIG_SYS_TEXT_BASE=0x47e00000
+CONFIG_SYS_TEXT_BASE=0x47E00000
 CONFIG_TARGET_M54451EVB=y
 CONFIG_SYS_EXTRA_OPTIONS="CF_SBF,SYS_STMICRO_BOOT,SYS_INPUT_CLKSRC=24000000"
 CONFIG_BOOTDELAY=1