nmi: backtrace: Allow runtime arch specific override

maillist inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8PLUM?from=project-issue
CVE: NA
Reference: https://lore.kernel.org/all/1604317487-14543-5-git-send-email-sumit.garg@linaro.org/



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Add a boolean return to arch_trigger_cpumask_backtrace() to support a
use-case where a particular architecture detects at runtime if it supports
NMI backtrace or it would like to fallback to default implementation using
SMP cross-calls.

Currently such an architecture example is arm64 supporting pseudo NMIs
feature which is only available on platforms which have support for GICv3
or later version.

Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Signed-off-by: Wei Li <liwei391@huawei.com>
Reviewed-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com>
Signed-off-by: Liao Chen <liaochen4@huawei.com>