If a resource is NULL, make sure we don't use an invalid descriptor
If a resource is NULL, make sure we don't use an invalid descriptor

* This can happen if the resource was not included in the capture, but
  there was a descriptor passed (i.e. not NULL desc which is handled
  separately) which specifies some parameters, but leaves the format
  as UNKNOWN.

TurtleRockStudios/renderdoc_public,Zorro666/renderdoc,michaelrgb/renderdoc,michaelrgb/renderdoc,TurtleRockStudios/renderdoc_public,cgmb/renderdoc,cgmb/renderdoc,baldurk/renderdoc,etnlGD/renderdoc,TurtleRockStudios/renderdoc_public,googlestadia/renderdoc,etnlGD/renderdoc,googlestadia/renderdoc,googlestadia/renderdoc,baldurk/renderdoc,michaelrgb/renderdoc,googlestadia/renderdoc,Zorro666/renderdoc,cgmb/renderdoc,googlestadia/renderdoc,Zorro666/renderdoc,Zorro666/renderdoc,TurtleRockStudios/renderdoc_public,etnlGD/renderdoc,Zorro666/renderdoc,googlestadia/renderdoc,baldurk/renderdoc,TurtleRockStudios/renderdoc_public,michaelrgb/renderdoc,baldurk/renderdoc,baldurk/renderdoc,cgmb/renderdoc,etnlGD/renderdoc,etnlGD/renderdoc,michaelrgb/renderdoc,baldurk/renderdoc,cgmb/renderdoc,etnlGD/renderdoc,TurtleRockStudios/renderdoc_public,Zorro666/renderdoc