gfx950 platform support

[zahiqbal]

gfx950 platform support added

[JehandadKhan]

Please cherry pick to rocm-main

cc @gulsumgudukbay

[mrodden]

This isn't gonna compile until we have an updated compiler with the gfx950 target available I guess.

From the CI logs

clang++: error: invalid target ID 'gfx950'; format is a processor name followed by an optional colon-delimited list of features followed by an enable/disable sign (e.g., 'gfx908:sramecc+:xnack-')

[mrodden]

Also, I think we're gonna need the changes from XLA to support this, so we would need to update the XLA_COMMIT to point to something with the gfx950 support available in XLA.

[mrodden]

Putting a request changes on this until the XLA side is merged.

Changing the default targets to include 950 probably won't work until the ROCM 6.5 release anyway, so we'll have to find another way to allow internal builds to add that to targets