[openwrt/openwrt] build: fix build for devices without initramfs

[LEDE Commits]

blocktrron pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/bb749e49a6e149f681a058b3d7e45fd8d4f79305

commit bb749e49a6e149f681a058b3d7e45fd8d4f79305
Author: David Bauer <mail at david-bauer.net>
AuthorDate: Tue Jun 8 19:30:12 2021 +0200

    build: fix build for devices without initramfs
    
    Don't attempt to copy initramfs images for devices which do not output
    an initramfs image.
    
    This was breaking builds for mpc85xx-p1010 since mid-march.
    
    Signed-off-by: David Bauer <mail at david-bauer.net>
---
 include/image.mk | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/image.mk b/include/image.mk
index 0d0e3eaba1..a7473abe68 100644
--- a/include/image.mk
+++ b/include/image.mk
@@ -478,7 +478,7 @@ define Device/Build/initramfs
 	  $$(if $$(CONFIG_JSON_OVERVIEW_IMAGE_INFO), $(BUILD_DIR)/json_info_files/$$(KERNEL_INITRAMFS_IMAGE).json,))
 
   $(KDIR)/$$(KERNEL_INITRAMFS_NAME):: image_prepare
-  $(1)-images: $(BIN_DIR)/$$(KERNEL_INITRAMFS_IMAGE)
+  $(1)-images: $$(if $$(KERNEL_INITRAMFS),$(BIN_DIR)/$$(KERNEL_INITRAMFS_IMAGE))
   $(BIN_DIR)/$$(KERNEL_INITRAMFS_IMAGE): $(KDIR)/tmp/$$(KERNEL_INITRAMFS_IMAGE)
 	cp $$^ $$@