Corrected installation instructions (render group and clinfo path)

[settle]

In Ubuntu 18.04.4 with ROCm 3.5.1 the full path to clinfo is /opt/rocm/opencl/bin/clinfo, not /opt/rocm/opencl/bin/x86_64/clinfo.

[settle]

@Rmalavally, @rkothako Can we update the installation instructions, especially now that Ubuntu 20.04 is officially supported? This PR partially duplicates #87 with respect to the incorrect clinfo path, but also includes the missing render group instructions requested in #83.

[pramenku]

Minor suggestion:

"render" groups is required only for Ubuntu20.04. For all other ROCm supported OSes, we need to continue use to "video" group only.

ROCm3.7 and future releases, clinfo path has been changed to “/opt/rocm/opencl/bin/clinfo”.

ROCm3.5 and older releases, clinfo path will be “/opt/rocm/opencl/bin/x86_64/clinfo”.

I would recommend better merge #94 instead of #87.

[Rmalavally]

Merging #94 after review from QA.

[YifeiLu-1]

ROCm3.7 and future releases, clinfo path has been changed to “/opt/rocm/opencl/bin/clinfo”.

ROCm3.5 and older releases, clinfo path will be “/opt/rocm/opencl/bin/x86_64/clinfo”.

x86_64 was not present in my previous ROCm3.5 install.

[rkothako]

Hi @YifeiLuDublin
Actually the change happened from 3.5 only.
Until 3.3, x86_64 was there, but from 3.5 on-wards, its removed.

[rkothako]

Hi @Rmalavally , please correct/update documentation if any.
/opt/rocm/opencl/bin/clinfo is from ROCm 3.5 only. Until 3.3, it was /opt/rocm/opencl/bin/x86_64/clinfo