Fix paths to weights in build_lib.sh for VivadoAccelator backend

[JanFSchulte]

Fixes crashes of part7a of the tutorial in v.1.0.0 reported in #1157.
These were found to be to a missing configuration of the path to the weight files in the VivadoAccelator background and thus a failure of the predict() function of the compiled model.

Fixed by explicitly setting the path in build_lib.sh in the VivadoAccelerator, copied from the same file in the Vivado backend.

Type of change

• Bug fix (non-breaking change that fixes an issue)

Tests

With v1.0.0 and the main branch, part7a of the tutorial crashes on the line

y_hls = hls_model.predict(np.ascontiguousarray(X_test))

With this fix, it no longer crashes.

Checklist

• I have read the guidelines for contributing.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• My changes generate no new warnings.
• I have installed and run pre-commit on the files I edited or added.
• I have added tests that prove my fix is effective or that my feature works.