Return channel in get system restart cause

The ipmi spec says that we should return the channel
as the last byte in get system restart cause. This was
not available when the command was originally written.
Now, it is available from the ipmi::Context

Tested: Check that channel in the response matches the
        channel the request came in on.

Change-Id: I6490c0b6fa41f78292aa002c17de39b31b7ee032
Signed-off-by: Vernon Mauery <vernon.mauery@linux.intel.com>
diff --git a/chassishandler.cpp b/chassishandler.cpp
index 4ca981d..0d31864 100644
--- a/chassishandler.cpp
+++ b/chassishandler.cpp
@@ -59,9 +59,6 @@
 static constexpr size_t addrTypeOffset = 16;
 static constexpr size_t ipAddrOffset = 17;
 
-static constexpr uint4_t RESERVED = 0;
-static constexpr uint8_t CHANNEL_NOT_SUPPORTED = 0;
-
 static constexpr size_t encIdentifyObjectsSize = 1;
 static constexpr size_t chassisIdentifyReqLength = 2;
 static constexpr size_t identifyIntervalPos = 0;
@@ -1294,8 +1291,9 @@
         return ipmi::responseUnspecifiedError();
     }
 
-    return ipmi::responseSuccess(cause.value(), RESERVED,
-                                 CHANNEL_NOT_SUPPORTED);
+    constexpr uint4_t reserved = 0;
+    auto channel = static_cast<uint8_t>(ctx->channel);
+    return ipmi::responseSuccess(cause.value(), reserved, channel);
 }
 
 //-------------------------------------------------------------