[openwrt/openwrt] build: fix uImage fake header command

[LEDE Commits]

mkresin pushed a commit to openwrt/openwrt.git, branch master:
https://git.lede-project.org/38bd4e4eb52002045134d00b9d3b0ab8d9d70cc4

commit 38bd4e4eb52002045134d00b9d3b0ab8d9d70cc4
Author: Mathias Kresin <dev at kresin.me>
AuthorDate: Thu Apr 19 19:09:11 2018 +0200

    build: fix uImage fake header command
    
    Use a syntax compatible with mkimage from u-boot 2018.03 to fix the
    build errors spotted by the build bot.
    
    The images are binary identical to the ones generated with mkimage from
    u-boot 2014.10.
    
    Signed-off-by: Mathias Kresin <dev at kresin.me>
---
 include/image-commands.mk | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/image-commands.mk b/include/image-commands.mk
index 0f9ac08..5f7845a 100644
--- a/include/image-commands.mk
+++ b/include/image-commands.mk
@@ -80,10 +80,11 @@ endef
 # append a fake/empty rootfs uImage header, to fool the bootloaders
 # rootfs integrity check
 define Build/append-uImage-fakeroot-hdr
-	rm -f $@.fakeroot
+	touch $@.fakeroot
 	$(STAGING_DIR_HOST)/bin/mkimage \
 		-A $(LINUX_KARCH) -O linux -T filesystem -C none \
 		-n '$(call toupper,$(LINUX_KARCH)) $(VERSION_DIST) fakeroot' \
+		-d $@.fakeroot \
 		-s \
 		$@.fakeroot
 	cat $@.fakeroot >> $@