arm: clean cache management

unify arm cache management except for non standard cache as ARM7TDMI

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
diff --git a/include/configs/pxa255_idp.h b/include/configs/pxa255_idp.h
index 5e2e7cf..7485f72 100644
--- a/include/configs/pxa255_idp.h
+++ b/include/configs/pxa255_idp.h
@@ -68,6 +68,9 @@
 
 #undef CONFIG_USE_IRQ			/* we don't need IRQ/FIQ stuff */
 
+/* we will never enable dcache, because we have to setup MMU first */
+#define CONFIG_SYS_NO_DCACHE
+
 /*
  * Size of malloc() pool
  */