International Residential Code, a reasonable index of what is
acceptable to code officials, says:
Separate the garage from the house with at least 1/2 inch gypsum board.
This holds for walls or ceilings.
Since the area above your particular garage appears to be more nearly
part of the garage than part of the house, an inspector might accept
gypsum board on the wall of the attic that connects with the house. I
won't predict what any given inspector willl do.

TB