opengl/context: remove unneeded ra_swapchain_fns redirection

We don't allow backends to override this anymore since
5ae0e0ff9a so we can just set it directly
in ra_swapchain.

video/out/opengl/context.c

@@ -79,7 +79,6 @@ struct priv {
     struct mp_log *log;
     struct ra_ctx_params params;
     struct opengl_opts *opts;
-    struct ra_swapchain_fns fns;
     GLuint main_fb;
     struct ra_tex *wrapped_fb; // corresponds to main_fb
     // for debugging:
@@ -130,6 +129,7 @@ bool ra_gl_ctx_init(struct ra_ctx *ctx, GL *gl, struct ra_ctx_params params)
     struct ra_swapchain *sw = ctx->swapchain = talloc_ptrtype(NULL, sw);
     *sw = (struct ra_swapchain) {
         .ctx = ctx,
+        .fns = &ra_gl_swapchain_fns,
     };
 
     struct priv *p = sw->priv = talloc_ptrtype(sw, p);
@@ -138,11 +138,8 @@ bool ra_gl_ctx_init(struct ra_ctx *ctx, GL *gl, struct ra_ctx_params params)
         .log    = ctx->log,
         .params = params,
         .opts   = mp_get_config_group(p, ctx->global, &opengl_conf),
-        .fns    = ra_gl_swapchain_fns,
     };
 
-    sw->fns = &p->fns;
-
     if (!gl->version && !gl->es)
         return false;