arm: start.S: Fix _TEXT_BASE for SPL

_TEXT_BASE must be set to CONFIG_SPL_TEXT_BASE for generic SPL, and to
CONFIG_SYS_TEXT_BASE for non-SPL builds.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Reviewed-by: Tom Rini <trini@ti.com>
diff --git a/arch/arm/cpu/arm720t/start.S b/arch/arm/cpu/arm720t/start.S
index 43bd6ed..1e3e5a1 100644
--- a/arch/arm/cpu/arm720t/start.S
+++ b/arch/arm/cpu/arm720t/start.S
@@ -85,7 +85,7 @@
 
 .globl _TEXT_BASE
 _TEXT_BASE:
-#ifdef CONFIG_SPL_BUILD
+#if defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_TEXT_BASE)
 	.word	CONFIG_SPL_TEXT_BASE
 #else
 	.word	CONFIG_SYS_TEXT_BASE