Open-p4studio cannot be built to support the real ASICs

[vgurevich]

After attempting to follow the instructions in RDC_README, I still could not build the open-p4studio to support the real hardware. The details can be found in my comments to #79 specifically this one:

Even after the workaround the build ended up in this failure:

2025-02-21 21:41:55,165: Begin bf-platforms setup
2025-02-21 21:41:55,166: CMake Error at CMakeLists.txt:256 (add_subdirectory):
2025-02-21 21:41:55,166:   add_subdirectory given source "pkgsrc/bf-platforms" which is not an
2025-02-21 21:41:55,166:   existing directory.

The culprit here is that pieces of the p4studio tool have also been removed from the community release, while the code in $SDE/CMakeFile.txt relies on those portions to extract the BSP code into $SDE/pkgsrc/bf-platforms directory.

For now, the workaround is: extract the bf-platforms-x.y.z package from the BSP into $SDE/pkgsrc/bf-platforms directory before starting the build. if you do that, it should complete successfully even when building for the real HW.