Prior to this patch, kth_order_egk_decode could read arbitrarily
large values which then overflowed and caused various issues.
Patch fixes this by making kth_order_egk_decode falliable,
requiring the caller to specify an upper bound and returning an
error if the read value would exceed that bound.
This patch resolves the same issue as
eb52251c0a, but I think this is the proper
fix as it also addresses issues with syntax elements besides
ff_vvc_num_signalled_palette_entries.
Signed-off-by: Frank Plowman <post@frankplowman.com>
7c5319e692