[Mesa-stable] Two cherry-picks for 12.0

[Ilia Mirkin]

Hello,

I fat-fingered a push and forgot to add stable tags to the following
two commits. They should both be included in 12.0. There will be more
:)

Thanks,

  -ilia

commit 1f895caba0accc0af3e637d6193ac0b673ce98bc
Author: Ilia Mirkin <imirkin at alum.mit.edu>
Date:   Sat May 28 14:28:07 2016 -0400

    nvc0/ir: limit max number of regs based on availability in SM

    This effectively limits registers to 32 and 64 for fermi and kepler when
    1024 threads are used, but allows the full amount to be used with
    smaller thread sizes.

    Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
    Reviewed-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>

commit 27a51ff9b420909334898785cf194b5998776e88
Author: Ilia Mirkin <imirkin at alum.mit.edu>
Date:   Sat May 28 14:23:35 2016 -0400

    nv50/ir: record number of threads in a compute shader

    Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
    Reviewed-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>