tools lib traceevent: Add correct header for ipv6 definitions

tools lib traceevent: Add correct header for ipv6 definitions

We need to include netinet/in.h to get the in6_addr struct definition, needed to
build it on the Android NDK:

  In file included from event-parse.c:36:0:
  /home/acme/android/android-ndk-r12/platforms/android-24/arch-arm/usr/include/netinet/ip6.h:82:18: error: field 'ip6_src' has incomplete type
    struct in6_addr ip6_src; /* source address */

And it is the canonical way of getting IPv6 definitions, as described,
for instance, in Linux's 'man ipv6'

Doing that uncovers another problem: this source file uses PRIu64 but
doesn't include it, depending on it being included by chance via the now
replaced header (netinet/ip6.h), fix it.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Chris Phlipot <cphlipot0@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-tilr31n3yaba1whsd47qlwa3@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>