Add for now some simple/basic query support (ie. things not actually
requiring the GPU).  Might change around a bit when I actually add
GPU queries, but for now this enables some useful performance info
in the GALLIUM_HUD.  For example:

  GALLIUM_HUD=fps+batches+batches-sysmem+batches-gmem+restores,draw-calls

The driver specific specific queries are:

  + draw-calls
  + batches - number of batches per second, sum of batches-sysmem
    plus batches-gmem
  + batches-gmem - render a set of tiles in GMEM, for each tile
    (optionally) system mem -> gmem (restore), plus N draws,
    plus gmem -> system mem (resolve) per second
  + batches-sysmem - N draws to system memory (GMEM bypass) per
    second
  + restores - number of GMEM batches that required restore per
    second

Ideally for GMEM rendering, you want batches-gmem to equal fps.  If
the app is doing something that triggers multiple passes (ie. requires
extra round trip gmem <-> system memory) then the # of batches per
second will go up relative to fps.

Signed-off-by: Rob Clark <robclark@freedesktop.org>