[openwrt/openwrt] realtek: fix ZyXEL initramfs image generation

[LEDE Commits]

chunkeey pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/daefc646e6d4f1f730c5957b5954b88abe7c00f3

commit daefc646e6d4f1f730c5957b5954b88abe7c00f3
Author: Bjørn Mork <bjorn at mork.no>
AuthorDate: Thu Jun 24 23:04:08 2021 +0200

    realtek: fix ZyXEL initramfs image generation
    
    The current rule produces empty trailers, causing the OEM firmware
    update application to reject our images.
    
    The double expansion of a makefile variable does not work inside
    shell code.  The second round is interpreted as a shell expansion,
    attempting to run the command ZYXEL_VERS instead of expanding the
    $(ZYXEL_VERS) makefile variable.
    
    Fix by removing one level of variable indirection.
    
    Fixes: c6c8d597e183 ("realtek: Add generic zyxel_gs1900 image definition")
    Tested-by: Sander Vanheule <sander at svanheule.net>
    Signed-off-by: Bjørn Mork <bjorn at mork.no>
---
 target/linux/realtek/image/Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/target/linux/realtek/image/Makefile b/target/linux/realtek/image/Makefile
index 5e4b4cde80..a7961970a3 100644
--- a/target/linux/realtek/image/Makefile
+++ b/target/linux/realtek/image/Makefile
@@ -10,7 +10,7 @@ DEVICE_VARS += ZYXEL_VERS
 
 define Build/zyxel-vers
        ( echo VERS;\
-       for hw in $(1); do\
+       for hw in $(ZYXEL_VERS); do\
                echo -n "V9.99($$hw.0) | ";\
                date -d @$(SOURCE_DATE_EPOCH) +%m/%d/%Y;\
        done ) >> $@
@@ -117,7 +117,7 @@ define Device/zyxel_gs1900
   IMAGE_SIZE := 6976k
   DEVICE_VENDOR := ZyXEL
   UIMAGE_MAGIC := 0x83800000
-  KERNEL_INITRAMFS := kernel-bin | append-dtb | gzip | zyxel-vers $$$$(ZYXEL_VERS) | \
+  KERNEL_INITRAMFS := kernel-bin | append-dtb | gzip | zyxel-vers | \
 	uImage gzip
 endef