vo_gpu: increase user shader size limit

The old size limit was chosen before LUT texture was supported in user
shader. At that time, the whole user shader will be compiled and run
on GPU, which makes large user shader impractical to be used.

With the introduction of LUT texture, the old size limit doesn't make
any sense. For example, a 1024x1024 rgba16f LUT will cost 32MB shader
size.

Fix this by increasing the size limit to a value that's unlikely be
reached.

video/out/gpu/video.c

@@ -472,7 +472,7 @@ static struct bstr load_cached_file(struct gl_video *p, const char *path)
             return p->files[n].body;
     }
     // not found -> load it
-    struct bstr s = stream_read_file(path, p, p->global, 1024000); // 1024 kB
+    struct bstr s = stream_read_file(path, p, p->global, 1000000000); // 1GB
     if (s.len) {
         struct cached_file new = {
             .path = talloc_strdup(p, path),