perf scripts python: Support syscall name parsing on arm64

In the result of "perf script syscall-counts" on arm64, the syscall
events are not resolved currently. Add "aarch64" to audit uname list to
support name parsing.

* After the patch:

[root@localhost ~]# perf script syscall-counts sleep 1
Press control+C to stop and show the summary

syscall events:

event count
---------------------------------------- -----------
mmap 6
close 5
mprotect 4
brk 3
newfstatat 3
openat 3
getrandom 1
prlimit64 1
munmap 1
clock_nanosleep 1
set_robust_list 1
set_tid_address 1
exit_group 1
read 1
faccessat 1

Signed-off-by: Wei Li <liwei391@huawei.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Li Bin <huawei.libin@huawei.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20230815131735.1237221-1-liwei391@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>