Change the signature of the command handler functions.

Resolves openbmc/openbmc#857

Change-Id: I0b7ca6665dd89629838a238d77aff67fec1818c7
Signed-off-by: Tom Joseph <tomjoseph@in.ibm.com>
diff --git a/command/payload_cmds.hpp b/command/payload_cmds.hpp
index 54b3f10..6901256 100644
--- a/command/payload_cmds.hpp
+++ b/command/payload_cmds.hpp
@@ -108,7 +108,7 @@
  *
  *  @return Response data for the command
  */
-std::vector<uint8_t> activatePayload(std::vector<uint8_t>& inPayload,
+std::vector<uint8_t> activatePayload(const std::vector<uint8_t>& inPayload,
                                      const message::Handler& handler);
 
 constexpr uint8_t IPMI_CC_PAYLOAD_DEACTIVATED = 0x80;
@@ -170,7 +170,7 @@
  *
  * @return Response data for the command.
  */
-std::vector<uint8_t> deactivatePayload(std::vector<uint8_t>& inPayload,
+std::vector<uint8_t> deactivatePayload(const std::vector<uint8_t>& inPayload,
                                        const message::Handler& handler);
 
 /** @struct GetPayloadStatusRequest
@@ -248,7 +248,7 @@
  *
  *  @return Response data for the command
  */
-std::vector<uint8_t> getPayloadStatus(std::vector<uint8_t>& inPayload,
+std::vector<uint8_t> getPayloadStatus(const std::vector<uint8_t>& inPayload,
                                       const message::Handler& handler);
 
 } // namespace command