[Mesa-stable] Additional changes to include in mesa 21.0

[Ilia Mirkin]

Sorry, left one out (it was still merging when I looked, ooops).
Please also include this into 21.0 (but I'd leave it out of the 20.3
series, not a big enough deal).

commit 245a696741d2a4cd5f2aade38c2194e3030d659b
Author: Ilia Mirkin <imirkin at alum.mit.edu>
Date:   Tue Jan 19 05:17:45 2021 -0500

    nvc0/ir: add fixup to deal with interpolateAtSample with non-MSAA

On Thu, Jan 21, 2021 at 4:02 PM Ilia Mirkin <imirkin at alum.mit.edu> wrote:
>
> Hi Dylan,
>
> Please include the following changes in the 21.0 branch. If you're
> making additional releases for 20.3, feel free to include them there
> as well:
>
> commit 55c42b7885701098cff9cc0fd0ffe08b0a90ea8b
> Author: Ilia Mirkin <imirkin at alum.mit.edu>
> Date:   Wed Jan 13 02:14:07 2021 -0500
>
>     st/mesa: fix broken moves for u2i64 and related ops
>
> commit 6638b58ccf17ce3a00a8ecbf5f39b5bedef238ed
> Author: Ilia Mirkin <imirkin at alum.mit.edu>
> Date:   Fri Jan 15 17:01:27 2021 -0500
>
>     nv50/ir: clear dnz flag when converting mul/mad to simpler ops
>
> Thanks,
>
>   -ilia