ipmi: start implementing flashHashFinish

Change-Id: I354b346bcd2d0dd141fd21a84e57cd7c06eadc1a
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/ipmi.cpp b/ipmi.cpp
index 50208d3..b9a8943 100644
--- a/ipmi.cpp
+++ b/ipmi.cpp
@@ -142,3 +142,17 @@
     (*dataLen) = 1;
     return IPMI_CC_OK;
 }
+
+ipmi_ret_t hashFinish(UpdateInterface* updater, const uint8_t* reqBuf,
+                      uint8_t* replyBuf, size_t* dataLen)
+{
+    if (!updater->hashFinish())
+    {
+        return IPMI_CC_INVALID;
+    }
+
+    /* We were successful and set the response byte to 0. */
+    replyBuf[0] = 0x00;
+    (*dataLen) = 1;
+    return IPMI_CC_OK;
+}