zink: simplify sampler bufferview change for non-db path

all bufferviews are deduplicated now, so this deref is unnecessary

Fixes: ef3f7989574 ("zink: prune zink_surface down to the imageview and create/fetch on demand")
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36269>
1 file changed