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/am57xx_evm_defconfig b/configs/am57xx_evm_defconfig
index 2556071..5d901d1 100644
--- a/configs/am57xx_evm_defconfig
+++ b/configs/am57xx_evm_defconfig
@@ -20,6 +20,7 @@
 # CONFIG_MISC_INIT_R is not set
 CONFIG_VERSION_VARIABLE=y
 CONFIG_BOARD_EARLY_INIT_F=y
+CONFIG_SPL_TEXT_BASE=0x40300000
 CONFIG_SPL_SYS_MALLOC_SIMPLE=y
 CONFIG_SPL_SEPARATE_BSS=y
 CONFIG_SPL_DMA_SUPPORT=y