Add Error Checks to PCI Functions and Reorganize libc Structure

[Galfurian]

Add Error Checks to PCI Functions and Reorganize libc Structure

Summary:

This pull request includes improvements for error handling in PCI functions, a fix for PCI bridge detection, and some file reorganizations.

Changes:

1. PCI Error Checks:

   • Added more error checks to ensure PCI functions handle edge cases properly.

2. Fix PCI Bridge Detection:

   • Corrected the detection of PCI bridges.

3. libc Reorganization:

   • Moved unistd.h to the root folder.
   • Added the ctime function.
   • Remove files from kernel side that are already inside the libc.

4. New Tests:

   • Added a test for the chdir function.

5. Merged Upstream Changes:

   • Integrated updates from the develop branch.

[fischerling]

Duplicate include.

[Galfurian]

Thanks!