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/medcom-wide_defconfig b/configs/medcom-wide_defconfig
index a66b1ba..ee9044e 100644
--- a/configs/medcom-wide_defconfig
+++ b/configs/medcom-wide_defconfig
@@ -7,6 +7,7 @@
 CONFIG_FIT=y
 CONFIG_OF_SYSTEM_SETUP=y
 CONFIG_SYS_STDIO_DEREGISTER=y
+CONFIG_SPL_TEXT_BASE=0x00108000
 CONFIG_SYS_PROMPT="Tegra20 (Medcom-Wide) # "
 # CONFIG_CMD_IMI is not set
 # CONFIG_CMD_FLASH is not set