nvc0: set sampler index mode to independently on gv100 compute

nvc0: set sampler index mode to independently on gv100 compute

We don't use linked texture/samplers. Fixes a bunch of CTS issues which
also seem to fail a bit randomly depending on what tests ran before and
such, so the list is incomplete.

Fixes:
KHR-GL46.texture_gather.*
KHR-GL46.compute_shader.resource-texture
KHR-GL46.multi_bind.dispatch_bind_samplers
KHR-GL46.multi_bind.dispatch_bind_textures
KHR-GL46.shading_language_420pack.binding_sampler_array
KHR-GL46.shading_language_420pack.binding_sampler_single
KHR-GL46.shading_language_420pack.binding_samplers
KHR-GL46.stencil_texturing.functional
KHR-GL46.texture_gather.incomplete-texture-last-comp

Signed-off-by: Karol Herbst <kherbst@redhat.com>
Reviewed-by: Ben Skeggs <bskeggs@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5874>