Description

This makes callers of get_eid_by_size able to distinguish the errors from success.

Related

Fixes #117

Testing

Ran an image with qemu-system-xtensa with -m 2M option and noticed that this error was present without patch but not with:

qemu-system-xtensa: [PSRAM] Invalid size 2MB for the PSRAM

Checklist

Before submitting a Pull Request, please ensure the following:

• 🚨 This PR does not introduce breaking changes.
• All CI checks (GH Actions) pass.
• Documentation is updated as needed.
• Tests are updated or added as necessary.
• Code is well-commented, especially in complex areas.
• Git history is clean — commits are squashed to the minimum necessary.