projects: ad5460: drop IIO_EXAMPLE

[amiclaus]

There is no IIO_EXAMPLE usage currenly in the project.

Fixes: dac70d6 ("projects: ad5460: add initial example")

Pull Request Description

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PR Type

• [x] Bug fix (change that fixes an issue)
• [ ] New feature (change that adds new functionality)
• [ ] Breaking change (has dependencies in other repos or will cause CI to fail)

PR Checklist

• [x] I have followed the Coding style guidelines
• [x] I have performed a self-review of the changes
• [ ] I have commented my code, at least hard-to-understand parts
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• [ ] I have tested in hardware affected projects, at the relevant boards
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