[source] image.mk: fix append-dtb race when multiple devices use the same .dts

[LEDE Commits]

nbd pushed a commit to source.git, branch master:
https://git.lede-project.org/?p=source.git;a=commitdiff;h=7bdc21de7241f779146be2dd7c77bb3a8067a672

commit 7bdc21de7241f779146be2dd7c77bb3a8067a672
Author: Felix Fietkau <nbd at nbd.name>
AuthorDate: Thu Jul 14 13:51:49 2016 +0200

    image.mk: fix append-dtb race when multiple devices use the same .dts
    
    Call Image/BuildDTB unconditionally to keep things consistent
    
    Signed-off-by: Felix Fietkau <nbd at nbd.name>
---
 include/image-commands.mk | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/image-commands.mk b/include/image-commands.mk
index 17ab46d..1128aea 100644
--- a/include/image-commands.mk
+++ b/include/image-commands.mk
@@ -39,8 +39,8 @@ define Build/tplink-safeloader
 endef
 
 define Build/append-dtb
-    $(if $(DEVICE_DTS_DIR),$(call Image/BuildDTB,$(DEVICE_DTS_DIR)/$(DEVICE_DTS).dts,$(DTS_DIR)/$(DEVICE_DTS).dtb))
-    cat $(DTS_DIR)/$(DEVICE_DTS).dtb >> $@
+	$(call Image/BuildDTB,$(if $(DEVICE_DTS_DIR),$(DEVICE_DTS_DIR),$(DTS_DIR))/$(DEVICE_DTS).dts,$@.dtb)
+	cat $@.dtb >> $@
 endef
 
 define Build/fit