Add: Get channel payload support command

Implemented Get Channel Payload Support command (IPMI Spec sec 24.8)
The same is implemented under channel commands, and will be
available for both Host & Net ipmid. Uses channel configuration
to differentiate between session / session-less channel

Tested-by:
1. Verified command executed successfully for session
based channel
ipmitool raw 6 0x4E 0x1 // Command
03 00 15 00 00 00 00 00 // Response
2. Verified sessionless channel error is returned.

Change-Id: I8b294234415b4467aeae6c23c192750471536f4e
Signed-off-by: Saravanan Palanisamy <saravanan.palanisamy@intel.com>
Signed-off-by: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>
diff --git a/user_channel/channelcommands.hpp b/user_channel/channelcommands.hpp
index c612d3f..abcead6 100644
--- a/user_channel/channelcommands.hpp
+++ b/user_channel/channelcommands.hpp
@@ -28,6 +28,7 @@
     IPMI_CMD_SET_CHANNEL_ACCESS = 0x40,
     IPMI_CMD_GET_CHANNEL_ACCESS = 0x41,
     IPMI_CMD_GET_CHANNEL_INFO = 0x42,
+    IPMI_CMD_GET_CHANNEL_PAYLOAD_SUPPORT = 0x4E,
 };
 
 void registerChannelFunctions();