Cycles: Re-enable HIPRT point cloud rendering

Previously point cloud rendering was disabled on the HIPRT backend due
to unexpected performance regressions introduce by it.

With the recent update to HIP SDK 6.3 and HIPRT 2.5, these performance
regressions have been resolved and so this commit re-enables
point cloud rendering on HIPRT.

Pull Request: https://projects.blender.org/blender/blender/pulls/134902

intern/cycles/kernel/device/hiprt/common.h

@@ -320,10 +320,7 @@ ccl_device_inline bool point_custom_intersect(const hiprtRay &ray,
                                               void *payload,
                                               hiprtHit &hit)
 {
-  /* Point cloud intersections are currently disabled to decrease register pressure in the ray
-   * tracing kernels. This increases the number of in-flight ray traversal waves, and fixes the
-   * performance regression reported in #127464 */
-#  if defined(__POINTCLOUD__) && 0
+#  if defined(__POINTCLOUD__)
   RayPayload *local_payload = (RayPayload *)payload;
   KernelGlobals kg = local_payload->kg;
   int object_id = kernel_data_fetch(user_instance_id, hit.instanceID);