st/nir: make st_nir_opts() available externally

The following patch will make use of this for asm style programs.

Reviewed-by: Eric Anholt <eric@anholt.net>

src/mesa/state_tracker/st_glsl_to_nir.cpp

@@ -314,7 +314,7 @@ st_nir_assign_uniform_locations(struct gl_context *ctx,
    *size = max;
 }
 
-static void
+void
 st_nir_opts(nir_shader *nir)
 {
    bool progress;

src/mesa/state_tracker/st_nir.h

@@ -42,6 +42,8 @@ void st_finalize_nir(struct st_context *st, struct gl_program *prog,
                      struct gl_shader_program *shader_program,
                      struct nir_shader *nir);
 
+void st_nir_opts(struct nir_shader *nir);
+
 bool
 st_link_nir(struct gl_context *ctx,
             struct gl_shader_program *shader_program);