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/cm_fx6_defconfig b/configs/cm_fx6_defconfig
index 62ee2b3..ce3f9de 100644
--- a/configs/cm_fx6_defconfig
+++ b/configs/cm_fx6_defconfig
@@ -20,6 +20,7 @@
 CONFIG_BOOTCOMMAND="run findfdt; run distro_bootcmd; run legacy_bootcmd"
 CONFIG_MISC_INIT_R=y
 CONFIG_BOUNCE_BUFFER=y
+CONFIG_SPL_TEXT_BASE=0x00908000
 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR=0x80
 CONFIG_SPL_I2C_SUPPORT=y
 CONFIG_SPL_SPI_LOAD=y