CVE-2023-54238: mlx5: fix skb leak while fifo resync and push

In the Linux kernel, the following vulnerability has been resolved:

mlx5: fix skb leak while fifo resync and push

During ptp resync operation SKBs were poped from the fifo but were never freed neither by napiconsume nor by devkfreeskbany. Add call to napiconsumeskb to properly free SKBs.

Another leak was happening because mlx5eskbfifohasroom() had an error in the check. Comparing free running counters works well unless C promotes the types to something wider than the counter. In this case counters are u16 but the result of the substraction is promouted to int and it causes wrong result (negative value) of the check when producer have already overlapped but consumer haven't yet. Explicit cast to u16 fixes the issue.