Fix AD4170 channel data reg read

[machschmitt]

AD4170 has a 3-byte size register for ADC data and ad4170 driver internals use a bit pre-pended to the register address to determine how many bytes to read. Fix AD4170 DATA_PER_CHANNEL register read by pre-pending the correct byte size bit to the channel data register address.

Fixes: 3c02acbb0c38 ("add ad4170 device driver")

Pull Request Description

Fixes AD4170 DATA_PER_CHANNEL register read. Bug reported by ADI application engineer.

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
• [ ] I have build all projects affected by the changes in this PR
• [ ] I have tested in hardware affected projects, at the relevant boards
• [x] I have signed off all commits from this PR
• [ ] I have updated the documentation (wiki pages, ReadMe etc), if applies