perf trace: Augment 'newstat' (aka 'stat') filename ptr

perf trace: Augment 'newstat' (aka 'stat') filename ptr

This one will need some more work, that 'statbuf' pointer requires a
beautifier in 'perf trace'.

  # perf trace -e tools/perf/examples/bpf/augmented_syscalls.c
     0.000 weechat/3596 stat(filename: /etc/localtime, statbuf: 0x7ffd87d11f60)
     0.186 perf/29818 openat(dfd: CWD, filename: /sys/kernel/debug/tracing/events/syscalls/sys_enter_stat/format)
     0.279 perf/29818 openat(dfd: CWD, filename: /sys/kernel/debug/tracing/events/syscalls/sys_enter_newstat/for)
     0.670 perf/29818 openat(dfd: CWD, filename: /sys/kernel/debug/tracing/events/syscalls/sys_enter_openat/form)
    60.805 DNS Res~er #20/21308 stat(filename: /etc/resolv.conf, statbuf: 0x7ffa733fe4a0)
    60.836 DNS Res~er #20/21308 open(filename: /etc/hosts, flags: CLOEXEC)
    60.931 perf/29818 openat(dfd: CWD, filename: /sys/kernel/debug/tracing/events/syscalls/sys_enter_open/format)
   607.070 DNS Res~er #21/29812 stat(filename: /etc/resolv.conf, statbuf: 0x7ffa5e1fe3f0)
   607.098 DNS Res~er #21/29812 open(filename: /etc/hosts, flags: CLOEXEC)
   999.336 weechat/3596 stat(filename: /etc/localtime, statbuf: 0x7ffd87d11f60)
^C#

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-4lhabe7m4uzo76lnqpyfmnvk@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>