ibm: Create p10bmc build target

Replace rainier with p10bmc as build target. Keep the rainier.conf as a
symlink to p10bmc.conf to allow the transition. Remove the rainier.conf
and the machine override from p10bmc.conf in a later commit to complete
the replacement.

Tested: Built rainier and p10bmc and checked for some files/service
        units to exist on both.

Change-Id: Ic8c8c6ffbc3507fbd9c692da259e37ae695359a6
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
diff --git a/meta-ibm/conf/conf-notes.txt b/meta-ibm/conf/conf-notes.txt
index f56b88b..d4578dc 100644
--- a/meta-ibm/conf/conf-notes.txt
+++ b/meta-ibm/conf/conf-notes.txt
@@ -2,11 +2,11 @@
 
 mihawk:
 DISTRO=openbmc-witherspoon MACHINE=mihawk bitbake obmc-phosphor-image
+p10bmc:
+DISTRO=openbmc-openpower MACHINE=p10bmc bitbake obmc-phosphor-image
 swift:
 DISTRO=openbmc-witherspoon MACHINE=swift bitbake obmc-phosphor-image
 witherspoon:
 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