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/smdk5250_defconfig b/configs/smdk5250_defconfig
index 2236e88..69b58f5 100644
--- a/configs/smdk5250_defconfig
+++ b/configs/smdk5250_defconfig
@@ -14,6 +14,7 @@
 CONFIG_SILENT_CONSOLE=y
 CONFIG_CONSOLE_MUX=y
 # CONFIG_SPL_FRAMEWORK is not set
+CONFIG_SPL_TEXT_BASE=0x02023400
 CONFIG_SYS_PROMPT="SMDK5250 # "
 CONFIG_CMD_GPIO=y
 CONFIG_CMD_I2C=y