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>

perf tools: Generate mips syscalls_n64.c syscall table

Grab a copy of arch/mips/kernel/syscalls/syscall_n64.tbl and use it to
generate tools/perf/arch/mips/include/generated/asm/syscalls_n64.c file,
this is similar with commit 1b700c997500 ("perf tools: Build syscall
table .c header from kernel's syscall_64.tbl")

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Juxin Gao <gaojuxin@loongson.cn>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Xuefeng Li <lixuefeng@loongson.cn>
Cc: linux-mips@vger.kernel.org
Link: http://lore.kernel.org/lkml/1612409724-3516-4-git-send-email-yangtiezhu@loongson.cn
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>