radeonsi: dump shader stats for shaderdb in one place

With the introduction of the live shader cache, when a shader is fetched from the cache no stats are printed for shaderdb. So in a sequence like this: vs1, fs1, vs1, fs2, shaderdb may see 3 or 4 lines, depending on the threads being used. If one run produces 3 lines while the other produces 4 lines, it would compare vs1 stats with fs2 stats.

This commit centralizes all calls to si_shader_dump_stats_for_shader_db in si_create_shader to avoid this issue.