flash-ipmi: implement flashHashData

Change-Id: Ib6a4f0219c623175562760461bffd0a45117d02e
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/flash-ipmi.cpp b/flash-ipmi.cpp
index f58363b..8fc9a52 100644
--- a/flash-ipmi.cpp
+++ b/flash-ipmi.cpp
@@ -166,7 +166,11 @@
 
 bool FlashUpdate::hashData(uint32_t offset, const std::vector<uint8_t>& bytes)
 {
-    /* TODO: implement. */
+    if (hashFd)
+    {
+        return writeBlock(hashFd, offset, bytes);
+    }
+
     return false;
 }