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/am3517_evm_defconfig b/configs/am3517_evm_defconfig
index c6accc6..4d3d02d 100644
--- a/configs/am3517_evm_defconfig
+++ b/configs/am3517_evm_defconfig
@@ -2,7 +2,7 @@
 # CONFIG_SPL_USE_ARCH_MEMCPY is not set
 # CONFIG_SPL_USE_ARCH_MEMSET is not set
 CONFIG_ARCH_OMAP2PLUS=y
-CONFIG_SYS_TEXT_BASE=0x80100000
+CONFIG_TEXT_BASE=0x80100000
 CONFIG_SYS_MALLOC_F_LEN=0x4000
 CONFIG_TI_COMMON_CMD_OPTIONS=y
 CONFIG_NR_DRAM_BANKS=2