Change to use the standard RMCP+ term

On the IPMI spec v2.0, the protocol for LAN is called RMCP+.
Change all the RCMP+ in the article to RMCP+.

Change-Id: Ie47521ede7a68688b4fe6cc65df76daa211d3129
Signed-off-by: Janny Au <jannya@hyvedesignsolutions.com>