[PATCH 8_9] Add block_write hook to block_dev_desc_t

Preparation for future patches which support block device writing

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/include/part.h b/include/part.h
index f89ebc6..4f5a570 100644
--- a/include/part.h
+++ b/include/part.h
@@ -45,6 +45,10 @@
 				      unsigned long start,
 				      lbaint_t blkcnt,
 				      unsigned long *buffer);
+	unsigned long	(*block_write)(int dev,
+				       unsigned long start,
+				       lbaint_t blkcnt,
+				       const void *buffer);
 }block_dev_desc_t;
 
 /* Interface types: */