gallium, radeonsi, iris, rusticl: Fixups for cl_khr_gl_sharing
What does this MR do and why?
Add PIPE_CAP_CL_GL_SHARING:
We have a situation where some drivers have all the required features, but they are not working with gl_sharing, so we end up advertising it wrongly. Add this cap to ensure this driver was tested to work with cl_khr_gl_sharing.
Make PIPE_CAP_PCI_.* optional:
These caps are not required for non PCIe devices, so return a bogus number.