xt_ipp2p: fix Soulseek false positive matches

xt_ipp2p: fix Soulseek false positive matches

According to the comment, the last match attempted is:

	14 00 00 00 01 yy 00 00 00 STRING(YY) 01 00 00 00 00 46|50 00 00 00 00

However, the conditional that inspects the last ten bytes is followed
by a semicolon, so the printk and return statements are executed
regard- less of what the last ten bytes are.

Remove the semicolon and only execute the printk and return if the
conditional expression is true.

Signed-off-by: Jeremy Sowden <jeremy@azazel.net>