netfilter: net/netfilter/ipvs/ip_vs_ftp.c: Remove use of NIPQUAD

NIPQUAD has very few uses left.

Remove this use and make the code have the identical form of the only
other use of "%u,%u,%u,%u,%u,%u" in net/ipv4/netfilter/nf_nat_ftp.c

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Patrick McHardy <kaber@trash.net>