Fix invalid pointer type for dns

Fix invalid pointer type for dns

The invalid pointer warning becomes an error in gcc14, and it turns out
it's actually an invalid pointer, because it expects a pointer to a
struct with a type tag and not just the IPv4 address, if we have IPv4
and IPv6 enabled (otherwise it typedefs to the IPv4 address and
everything is fine).

Github-fixes: #59
Signed-off-by: Michael Pucher <contact@cluo.sh>
Approved-by: Razvan Deaconescu <razvand@unikraft.io>
Reviewed-by: Razvan Deaconescu <razvand@unikraft.io>
GitHub-Closes: #60