perf tools: Declare syscalltbl_*[] as const for all archs

syscalltbl_*[] should never be changing, let us declare it as const.

Suggested-by: Ian Rogers <irogers@google.com>
Reviewed-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: loongarch@lists.linux.dev
Link: https://lore.kernel.org/r/1685441401-8709-2-git-send-email-yangtiezhu@loongson.cn


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>