[openwrt/openwrt] kirkwood: fix sysupgrade

[LEDE Commits]

mkresin pushed a commit to openwrt/openwrt.git, branch master:
https://git.lede-project.org/a7e62b4be1dac8e98a816ad9b11d0b8ff7620dd7

commit a7e62b4be1dac8e98a816ad9b11d0b8ff7620dd7
Author: 尤晓杰 <yxj790222 at 163.com>
AuthorDate: Wed Jan 17 21:03:50 2018 +0800

    kirkwood: fix sysupgrade
    
    The platform_check_image() stub need to return 0 for success, otherwise
    the sysupgrade will fail with:
    
      Image check 'platform_check_image' failed.
    
    Fixes: aa6f5f1787a6 ("kirkwood: use image metadata")
    Signed-off-by: 尤晓杰 <yxj790222 at 163.com>
    [reworded commit message}
    Signed-off-by: Mathias Kresin <dev at kresin.me>
---
 target/linux/kirkwood/base-files/lib/upgrade/platform.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/target/linux/kirkwood/base-files/lib/upgrade/platform.sh b/target/linux/kirkwood/base-files/lib/upgrade/platform.sh
index 27012bd..a25d90a 100644
--- a/target/linux/kirkwood/base-files/lib/upgrade/platform.sh
+++ b/target/linux/kirkwood/base-files/lib/upgrade/platform.sh
@@ -4,7 +4,7 @@ RAMFS_COPY_DATA='/etc/fw_env.config /var/lock/fw_printenv.lock'
 REQUIRE_IMAGE_METADATA=1
 
 platform_check_image() {
-	return 1
+	return 0
 }
 
 platform_do_upgrade() {