Rename CONFIG_SYS_TEXT_BASE to CONFIG_TEXT_BASE

The current name is inconsistent with SPL which uses CONFIG_SPL_TEXT_BASE
and this makes it imposible to use CONFIG_VAL().

Rename it to resolve this problem.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/octeontx_81xx_defconfig b/configs/octeontx_81xx_defconfig
index c4a22cf..dbf5617 100644
--- a/configs/octeontx_81xx_defconfig
+++ b/configs/octeontx_81xx_defconfig
@@ -1,7 +1,7 @@
 CONFIG_ARM=y
 # CONFIG_ARM64_SUPPORT_AARCH32 is not set
 CONFIG_ARCH_OCTEONTX=y
-CONFIG_SYS_TEXT_BASE=0x2800000
+CONFIG_TEXT_BASE=0x2800000
 CONFIG_SYS_MALLOC_LEN=0x4008000
 CONFIG_SYS_MALLOC_F_LEN=0x4000
 CONFIG_NR_DRAM_BANKS=1