meta-ibm: Add rainier to example build invocations

This is the configuration that CI builds.

Signed-off-by: Joel Stanley <joel@jms.id.au>
Change-Id: Ib9b2ccc554f7ca2c602cec57a300416105791412
diff --git a/meta-ibm/conf/conf-notes.txt b/meta-ibm/conf/conf-notes.txt
index f877231..f56b88b 100644
--- a/meta-ibm/conf/conf-notes.txt
+++ b/meta-ibm/conf/conf-notes.txt
@@ -8,3 +8,5 @@
 DISTRO=openbmc-witherspoon MACHINE=witherspoon bitbake obmc-phosphor-image
 witherspoon-tacoma:
 DISTRO=openbmc-openpower MACHINE=witherspoon-tacoma bitbake obmc-phosphor-image
+rainier:
+DISTRO=openbmc-openpower MACHINE=rainier bitbake obmc-phosphor-image