perf machine: Use true and false for bool variable

perf machine: Use true and false for bool variable

Fix the following coccicheck warnings:

./tools/perf/util/machine.c:2000:9-10: WARNING: return of 0/1 in
function 'symbol__match_regex' with return type bool.

Committer notes:

Found this in the pile, it was already returning bool, but this patch
simplifies it further, from 3 lines to just 1.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Suggested-by: David Laight <David.Laight@ACULAB.COM>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org
Link: https://lore.kernel.org/r/1614247483-102665-1-git-send-email-jiapeng.chong@linux.alibaba.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>