Move Palmetto specific metadata to Palmetto layer
diff --git a/meta-palmetto/conf/machine/palmetto.conf b/meta-palmetto/conf/machine/palmetto.conf
index f846787..82a9b1c 100644
--- a/meta-palmetto/conf/machine/palmetto.conf
+++ b/meta-palmetto/conf/machine/palmetto.conf
@@ -19,6 +19,8 @@
        "
 
 # UBOOT_MACHINE_${MACHINE} = "${MACHINE}_config
+KMACHINE = "aspeed"
+KERNEL_DEVICETREE = "${KMACHINE}-bmc-opp-${MACHINE}.dtb"
 
 require conf/machine/include/ast2400.inc
 require conf/machine/include/obmc-bsp-common.inc