perf trace: Allow configuring if zeroed syscall args should be printed

The default so far, since we show argument names followed by its values,
was to make the output more compact by suppressing most zeroed args.

Make this configurable so that users can choose what best suit their
needs.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-q0gxws02ygodh94o0hzim5xd@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Documentation/perf-config.txt

@@ -528,6 +528,8 @@ trace.*::
 		The initial use case is to add augmented_raw_syscalls.o to
 		activate the 'perf trace' logic that looks for syscall
 		pointer contents after the normal tracepoint payload.
+	trace.show_zeros::
+		Do not suppress syscall arguments that are equal to zero.
 
 SEE ALSO
 --------