meta-facebook: harma: use common uboot dts

Revise the uboot path to ast2600-facebook.

Change-Id: I5d02c42c5fd657321abd717e66f802479aee4275
Signed-off-by: Peter Yin <peter.yin@quantatw.com>
diff --git a/meta-facebook/meta-harma/conf/machine/harma.conf b/meta-facebook/meta-harma/conf/machine/harma.conf
index 2454694..be5086a 100644
--- a/meta-facebook/meta-harma/conf/machine/harma.conf
+++ b/meta-facebook/meta-harma/conf/machine/harma.conf
@@ -4,7 +4,7 @@
 KERNEL_DEVICETREE = "aspeed/${KMACHINE}-bmc-facebook-${MACHINE}.dtb"
 
 UBOOT_MACHINE = "ast2600_openbmc_spl_defconfig"
-UBOOT_DEVICETREE = "ast2600-bletchley"
+UBOOT_DEVICETREE = "ast2600-facebook"
 
 SPL_BINARY = "spl/u-boot-spl.bin"
 SOCSEC_SIGN_ENABLE = "0"