MAINTAINERS: add new maintainers for Nuvoton NPCX platforms

[ChiHuaL]

Add Nuvoton guys, TomChang19 and Alvsun, in maintainers of Nuvoton NPCX platforms and remove them from collaborators.

[kartben]

@ChiHuaL can you elaborate on why you need this many - 4 maintainers seems like a lot :) Maybe there is a way to split in multiple areas?

[ChiHuaL]

@ChiHuaL can you elaborate on why you need this many - 4 maintainers seems like a lot :) Maybe there is a way to split in multiple areas?

We found TomChang19 and Alvsun cannot add the backport tag for PRs made by Nuvoton. (The gear icon does not show in their web UI with their account.)
We believe the reason should be they are the collaborators but the maintainers.
That's the motivation we like them in the maintainer list.

[kartben]

@ChiHuaL can you elaborate on why you need this many - 4 maintainers seems like a lot :) Maybe there is a way to split in multiple areas?

We found TomChang19 and Alvsun cannot add the backport tag for PRs made by Nuvoton. (The gear icon does not show in their web UI with their account.) We believe the reason should be they are the collaborators but the maintainers. That's the motivation we like them in the maintainer list.

No, the reason is that they should be added as contributors to the zephyr-rtos GitHub organization. This was probably an oversight when they got added to the MAINTAINERS file and no one checked they were contributors already (or they never accepted the invite from GitHub)
Please apply here: https://github.com/zephyrproject-rtos/zephyr/issues/new?assignees=&labels=Role+Nomination&projects=&template=006_nomination.md&title=

@TomChang19 @alvsun

[kartben]

Please consider closing the PR if my comment above addresses your original intent