pktcdvd: Get rid of pkt_seq_show() forward declaration

The code can be neater without forward declarations.
Get rid of pkt_seq_show() forward declaration. This
will also allow futher cleanups to be cleaner.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20230310164549.22133-5-andriy.shevchenko@linux.intel.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>