Add support for Vega 64

[ekuznetsov139]

Resolves #653

In the long run, a more reliable way of identifying the hardware is needed (why not just go by gfx***?)

[saadrahim]

@amcamd @leekillough This looks like a useful commit with little risk. @yoichiyoshida says a corresponding commit is needed in Tensile as well. Should we do both and close this PR? Seems like a waste of CI cycles to keep this PR open without doing anything.

[ekuznetsov139]

I guess they are just not used to getting PRs from strangers and they don't know what to do. I have two more PRs against Tensile in the same state (open with no activity for coming up on 3 weeks).

BTW, here are some more Vega 10 device strings not currently recognized by rocBLAS:

Vega 10 [Radeon Instinct MI25]
Radeon PRO V320
Radeon Pro Vega 64
Vega 10 [Radeon PRO WX 8100]
Vega 10 XT [Radeon PRO WX 9100]
Vega 10 XT [Radeon PRO SSG]
Vega 10 XL [Radeon Pro Vega 56]
Vega 10 [Radeon Instinct MI25 MxGPU]

All these names are coming from http://mirrors.kernel.org/ubuntu/pool/main/p/pciutils/pciutils_3.5.2-1ubuntu1.1_i386.deb (the most recent update for 18.04LTS).

If you go to the master version of pci.ids (http://pciids.sourceforge.net/v2.2/pci.ids), you'll see even more, for example, my card (687f) becomes "Vega 10 XL/XT [Radeon RX Vega 56/64]".

If I were an owner of a $10K Radeon Instinct MI25, I'd probably hate to discover that I'm getting fallback performance because my card is not recognized as a legit Vega 10.

[saadrahim]

We need corresponding changes in Tensile and additional GPUs need to be added. An AMD engineer will follow up.

[amcamd]

Thank you for the contribution. Sorry for the delay in merging your work.