Convert CONFIG_TPL_TEXT_BASE to Kconfig

This converts the following to Kconfig:
   CONFIG_TPL_TEXT_BASE

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/P1020RDB-PD_NAND_defconfig b/configs/P1020RDB-PD_NAND_defconfig
index cc3a1f6..130dea9 100644
--- a/configs/P1020RDB-PD_NAND_defconfig
+++ b/configs/P1020RDB-PD_NAND_defconfig
@@ -6,6 +6,7 @@
 CONFIG_DEFAULT_DEVICE_TREE="p1020rdb-pd"
 CONFIG_SPL_TEXT_BASE=0xFF800000
 CONFIG_SPL_SERIAL=y
+CONFIG_TPL_TEXT_BASE=0xF8F81000
 CONFIG_TPL_LIBCOMMON_SUPPORT=y
 CONFIG_TPL_LIBGENERIC_SUPPORT=y
 CONFIG_SPL=y