build: image: fix build breakage of some images
Commit 881ed09ee6e2 ("build: create JSON files containing image info")
has removed the crucial empty new line from the image copy step
resulting in the following errors during make function expansion:
GZ_SUFFIX :=
bash: GZ_SUFFIX: command not found
Makefile:86: recipe for target 'openwrt-ath79-generic-tplink_archer-c7-v5-squashfs-sysupgrade.bin' failed
Fixes: 881ed09ee6e2 ("build: create JSON files containing image info")
Signed-off-by: Petr Štetiar <[email protected]>
Petr Štetiar