ipvs: Mark tcp/udp v4 and v6 debug functions static

They are only used in this file, so they should be static

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Acked-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>