hk: fix unaligned copies

Fixes regression in Deus Ex: Human Revolution (DX11) via DXVK reported by James
Calligeros.

Pending CTS coverage: https://gitlab.khronos.org/Tracker/vk-gl-cts/-/issues/5640



Only the alignment check here is load bearing but I clarified the logic while at
it.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>