configs: move CONFIG_SPL_TEXT_BASE to Kconfig

Moved CONFIG_SPL_TEXT_BASE to common/spl/Kconfig and migrate existing
values.

Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
[trini: Re-run migration]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/devkit8000_defconfig b/configs/devkit8000_defconfig
index 8bb55b6..da09b3a 100644
--- a/configs/devkit8000_defconfig
+++ b/configs/devkit8000_defconfig
@@ -8,6 +8,7 @@
 # CONFIG_USE_BOOTCOMMAND is not set
 CONFIG_SYS_CONSOLE_INFO_QUIET=y
 CONFIG_VERSION_VARIABLE=y
+CONFIG_SPL_TEXT_BASE=0x40200000
 CONFIG_SPL_OS_BOOT=y
 # CONFIG_CMD_IMI is not set
 CONFIG_CMD_SPL=y