arm, at91: enable thumb mode for taurus board in SPL

Signed-off-by: Heiko Schocher <hs@denx.de>
diff --git a/include/configs/taurus.h b/include/configs/taurus.h
index 20194ae..06725cd 100644
--- a/include/configs/taurus.h
+++ b/include/configs/taurus.h
@@ -26,6 +26,11 @@
 
 #define CONFIG_SYS_GENERIC_BOARD
 
+#if defined(CONFIG_SPL_BUILD)
+#define CONFIG_SYS_THUMB_BUILD
+#define CONFIG_SYS_ICACHE_OFF
+#define CONFIG_SYS_DCACHE_OFF
+#endif
 /*
  * Warning: changing CONFIG_SYS_TEXT_BASE requires
  * adapting the initial boot program.