ir3/legalize: add syncs based on previous instr to sync_update

sync_update currently only deals with the current instruction but there
are a few cases where syncs depend on the previous instruction (e.g.,
barriers). Add those to sync_update/ir3_required_sync_flags to have all
the sync logic centralized.

Signed-off-by: Job Noorman <jnoorman@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34108>
1 file changed