meta-ibm: Configure rainier machine for new u-boot

This selects the ast2600 openbmc u-boot configuration and the rainier
device tree.

Change-Id: I8696d509aff3788ac65d875da80235a0d34e2c05
Signed-off-by: Joel Stanley <joel@jms.id.au>
diff --git a/meta-witherspoon/conf/machine/rainier.conf b/meta-witherspoon/conf/machine/rainier.conf
index 78ffbbc..1f8c21e 100644
--- a/meta-witherspoon/conf/machine/rainier.conf
+++ b/meta-witherspoon/conf/machine/rainier.conf
@@ -1,5 +1,6 @@
 KERNEL_DEVICETREE = "aspeed-bmc-ibm-rainier.dtb"
-UBOOT_MACHINE = "evb-ast2600_defconfig"
+UBOOT_MACHINE = "ast2600_openbmc_defconfig"
+UBOOT_DEVICETREE = "ast2600-rainier"
 
 OBMC_POWER_SUPPLY_INSTANCES = "0 1 2 3"