zink: fix batch disambiguation on first submit

zink: fix batch disambiguation on first submit

submit_count is used to disambiguate a batch_id based on the generation
id of a given batch: this value is incremented once on submit and once on
reset such that the diff of the values is > 1 any time the batch does not
represent the fence it was last submitted with

in the case of a batch's first use, however, this value was being incorrectly
incremented such that the first submit would cause disambiguation checks
to erroneously determine that the batch had already completed, breaking synchronization

fixes #9313

cc: mesa-stable

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24016>