gallium: remove pipe_driver_query_group_info field type

gallium: remove pipe_driver_query_group_info field type

This was only used to implement an unnecessarily restrictive interpretation
of the spec of AMD_performance_monitor. The spec says

  A performance monitor consists of a number of hardware and software
  counters that can be sampled by the GPU and reported back to the
  application.

I guess one could take this as a requirement that counters _must_ be sampled
by the GPU, but then why are they called _software_ counters? Besides,
there's not much reason _not_ to expose all counters that are available,
and this simplifies the code.

v3: add a missing change in the nouveau driver (thanks Samuel Pitoiset)

Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Tested-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>