Allow NXP targets to override all lwIP settings

[MateuszKlatecki]

Description

• Allow FreeRTOS targets to override all lwIP settings.

Motivation and Context

Allow end developer freedom to configure lwIP

How Has This Been Tested?

Screenshots

Types of changes

• Improvement (non-breaking change that improves a feature, code or algorithm)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Config and build (change in the configuration and build system, has no impact on code or features)
• Dependencies (update dependencies and changes associated, has no impact on code or features)
• Unit Tests (work on Unit Tests, has no impact on code or features)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[nfbot]

@MateuszKlatecki there are issues with the code style on the source files.
A PR was submitted with the code style fixes. Please review and merge the changes. See https://github.com/MateuszKlatecki/nf-interpreter/pull/1.

Make sure you are using the project code style. Check the details here.

[josesimoes]

Makes perfect sense!
And the #ifdef checks where wrongly removed in #1885. They belong here.