Fixes

 - switch to volatile everywhere
 - use myusec_delay instead of usleep

Corresponding to coreboot v1 svn r492.
diff --git a/flash.h b/flash.h
index 3b763a7..1828176 100644
--- a/flash.h
+++ b/flash.h
@@ -6,7 +6,7 @@
 	int manufacture_id;
 	int model_id;
 
-	char * virt_addr;
+	volatile char * virt_addr;
 	int total_size;
 	int page_size;