freedreno: Log the number of loops in the shader for shader-db.

freedreno: Log the number of loops in the shader for shader-db.

shader-db's report.py will use this to see when we've changed loop
unrolling behavior on a shader and skip including other stats like
instruction count from being considered for that shader, since they won't
be useful as a proxy for real world performance in that case.

Reviewed-by: Rob Clark <robdclark@gmail.com>
Tested-by: Eduardo Lima Mitev <elima@igalia.com>