Move mesa_to_tgsi.[ch] into state tracker.

diff --git a/src/mesa/pipe/tgsi/mesa/mesa_to_tgsi.c b/src/mesa/state_tracker/st_mesa_to_tgsi.c
similarity index 100%
rename from src/mesa/pipe/tgsi/mesa/mesa_to_tgsi.c
rename to src/mesa/state_tracker/st_mesa_to_tgsi.c

diff --git a/src/mesa/pipe/tgsi/mesa/mesa_to_tgsi.h b/src/mesa/state_tracker/st_mesa_to_tgsi.h
similarity index 100%
rename from src/mesa/pipe/tgsi/mesa/mesa_to_tgsi.h
rename to src/mesa/state_tracker/st_mesa_to_tgsi.h