IIO: extend types

[rbudai98]

Add power as IIO channel type

Pull Request Description

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PR Type

• 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

• I have followed the Coding style guidelines
• I have complied with the Submission Checklist
• I have performed a self-review of the changes
• I have commented my code, at least hard-to-understand parts
• I have build all projects affected by the changes in this PR
• I have tested in hardware affected projects, at the relevant boards
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• I have updated the documentation (wiki pages, ReadMe etc), if applies