dynamic_debug: add support for print stack

dynamic_debug: add support for print stack

In practical problem diagnosis, especially during the boot phase, it is
often desirable to know the call sequence.  However, currently, apart from
adding print statements and recompiling the kernel, there seems to be no
good alternative.  If dynamic_debug supported printing the call stack, it
would be very helpful for diagnosing issues.  This patch add support '+d'
for dump stack.

Link: https://lkml.kernel.org/r/20251025080003.312536-1-yebin@huaweicloud.com
Signed-off-by: Ye Bin <yebin10@huawei.com>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>