FAFT: Fix firmware_TPMKernelVersion by calling APIs to get kernel versions

tcsd/trunksd is no longer stopped when running a FAFT test. Fix the test
firmware_TPMKernelVersion by calling the related APIs which will stopped
tcsd/trunksd during reading the TPM NVRAM data.

BUG=chrome-os-partner:62150
TEST=Ran firmware_TPMKernelVersion and passed the modified code.

Change-Id: If55fa20c9709fa7e881e615ab04a49f6025820f2
Reviewed-on: https://chromium-review.googlesource.com/436244
Commit-Ready: Wai-Hong Tam <waihong@google.com>
Tested-by: Wai-Hong Tam <waihong@google.com>
Reviewed-by: Andrey Pronin <apronin@chromium.org>
diff --git a/client/cros/faft/rpc_functions.py b/client/cros/faft/rpc_functions.py
index 47d2df6..90d8213 100755
--- a/client/cros/faft/rpc_functions.py
+++ b/client/cros/faft/rpc_functions.py
@@ -630,7 +630,15 @@
 
     def _tpm_get_firmware_datakey_version(self):
         """Retrieve tpm firmware data key version."""
-        return self._tpm_handler.get_fw_body_version()
+        return self._tpm_handler.get_fw_key_version()
+
+    def _tpm_get_kernel_version(self):
+        """Retrieve tpm kernel body version."""
+        return self._tpm_handler.get_kernel_version()
+
+    def _tpm_get_kernel_datakey_version(self):
+        """Retrieve tpm kernel data key version."""
+        return self._tpm_handler.get_kernel_key_version()
 
     def _cgpt_get_attributes(self):
         """Get kernel attributes."""