drivers: platform: maxim: Simplify irq_register_callback

[CiprianRegus]

Pull Request Description

Currently max_irq_register_callback() explicitly uses an event name instead of callback_desc->event for no reason. This results in having to repeat the create/update callback list seqence for each event type. Fix this by accesing callback_desc->event instead.

Also, in case we already have an action registered, make sure the MCU specific configuration successfully completes before updating the action.

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

• [x] I have followed the Coding style guidelines
• [x] I have performed a self-review of the changes
• [x] 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