i965: silence unused var warnings in non-debug builds

Reviewed-by: Chad Versace <chad@chad-versace.us>

src/mesa/drivers/dri/i965/brw_fs.cpp

@@ -1773,6 +1773,7 @@ fs_visitor::run()
 
       /* Make sure we didn't try to sneak in an extra uniform */
       assert(orig_nr_params == c->prog_data.nr_params);
+      (void) orig_nr_params;
    }
 
    return !failed;

src/mesa/drivers/dri/i965/brw_wm.c

@@ -467,6 +467,7 @@ static void brw_prepare_wm_prog(struct brw_context *brw)
 			 &brw->wm.prog_offset, &brw->wm.prog_data)) {
       bool success = do_wm_prog(brw, ctx->Shader.CurrentFragmentProgram, fp,
 				&key);
+      (void) success;
       assert(success);
    }
 }