Update libpldm api encode_*_req functions to have payload_length param

There were a few of the APIs in libpldm's fru and platform
that Hostboot was using downstream that did not have the
payload_length param which the Hostboot templates expect. All
encode_*_req functions should end with a payload_length parameter
and this commit moves us towards that goal.

Tested: I ran run-unit-test-docker.sh from the openbmc-build-scripts
repo with the script pointed at my pldm directory.

Change-Id: Ief825111970db2faffaf00e431bc0f43f7a11b02
Signed-off-by: Christian Geddes <crgeddes@us.ibm.com>
diff --git a/libpldm/platform.h b/libpldm/platform.h
index cab1804..cafd47c 100644
--- a/libpldm/platform.h
+++ b/libpldm/platform.h
@@ -1056,12 +1056,10 @@
  * @note Caller is responsible for memory alloc and dealloc of param
  * 'msg.payload'
  */
-int encode_platform_event_message_req(uint8_t instance_id,
-				      uint8_t format_version, uint8_t tid,
-				      uint8_t event_class,
-				      const uint8_t *event_data,
-				      size_t event_data_length,
-				      struct pldm_msg *msg);
+int encode_platform_event_message_req(
+    uint8_t instance_id, uint8_t format_version, uint8_t tid,
+    uint8_t event_class, const uint8_t *event_data, size_t event_data_length,
+    struct pldm_msg *msg, size_t payload_length);
 
 /** @brief Decode PlatformEventMessage response data
  * @param[in] msg - Request message