netfilter: xt_hashlimit does a wrong SEQ_SKIP

The function dl_seq_show() returns 1 (equal to SEQ_SKIP) in case
a seq_printf() call return -1.  It should return -1.

This SEQ_SKIP behavior brakes processing the proc file e.g. via a
pipe or just through less.

Signed-off-by: Jesper Dangaard Brouer <hawk@comx.dk>
Signed-off-by: Patrick McHardy <kaber@trash.net>