ibm: rainier: Add p10bmc as MACHINEOVERRIDES

The IBMC POWER10 systems will have a common BMC image, therefore there
will be a transition to move from the 'rainier' system name to the
generic 'p10bmc' name.

This will be done in two stages. The first one is to create a p10bmc
MACHINEOVERRIDES and replace the rainier conditionals with p10bmc.

Once that's done, the rainier.conf will be replaced with p10bmc.conf.

Change-Id: Ic499d36dd7f74a8b7f4a44723f76d1e344e15a32
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
diff --git a/meta-ibm/conf/machine/rainier.conf b/meta-ibm/conf/machine/rainier.conf
index f5152f7..19df5be 100644
--- a/meta-ibm/conf/machine/rainier.conf
+++ b/meta-ibm/conf/machine/rainier.conf
@@ -5,6 +5,7 @@
 
 OBMC_POWER_SUPPLY_INSTANCES = "0 1 2 3"
 
+MACHINEOVERRIDES =. "p10bmc:"
 require conf/machine/include/ast2600.inc
 require conf/machine/include/obmc-bsp-common.inc
 require conf/machine/include/openpower.inc