mesa/st: Remove st_glsl_to_tgsi.

It is no longer called, and can be retired.

Fixes: #1924, #822, #6073

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8044>

src/mesa/program/program.c

@@ -45,7 +45,6 @@
 #include "util/u_atomic.h"
 
 #include "state_tracker/st_program.h"
-#include "state_tracker/st_glsl_to_tgsi.h"
 #include "state_tracker/st_context.h"
 
 /**
@@ -250,9 +249,6 @@ _mesa_delete_program(struct gl_context *ctx, struct gl_program *prog)
 
    st_release_variants(st, prog);
 
-   if (prog->glsl_to_tgsi)
-      free_glsl_to_tgsi_visitor(prog->glsl_to_tgsi);
-
    free(prog->serialized_nir);
 
    if (prog == &_mesa_DummyProgram)