pxa: Disable dcache on palmld, palmtc, zipitz2

These platforms don't include dcache support. Define CONFIG_SYS_DCACHE_OFF
so that functions don't try to call non-existent routines like
flush_dcache_range().

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>
diff --git a/include/configs/palmld.h b/include/configs/palmld.h
index c5dd494..3f9802c 100644
--- a/include/configs/palmld.h
+++ b/include/configs/palmld.h
@@ -28,6 +28,9 @@
 #define	CONFIG_CPU_PXA27X		1	/* Marvell PXA270 CPU */
 #define	CONFIG_PALMLD		1	/* Palm LifeDrive board */
 
+/* we will never enable dcache, because we have to setup MMU first */
+#define CONFIG_SYS_DCACHE_OFF
+
 /*
  * Environment settings
  */