tools: scripts: linux: Add mandatory post_build target

[dbogdan]

Fixing: *** No rule to make target 'linux_post_build', needed by 'post_build'

Pull Request Description

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• [x] Bug fix (change that fixes an issue)
• [ ] New feature (change that adds new functionality)
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[buha]

yeah this was introduced recently, there were changes related to this and linux platform was not tested