stacktrace: Export stack_trace_save_tsk

The bcachefs module wants it, and there doesn't seem to be any
reason it shouldn't be exported like the other functions.
Signed-off-by: Christopher James Halse Rogers <raof@ubuntu.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

kernel/stacktrace.c

@@ -151,6 +151,7 @@ unsigned int stack_trace_save_tsk(struct task_struct *tsk, unsigned long *store,
 	put_task_stack(tsk);
 	return c.len;
 }
+EXPORT_SYMBOL_GPL(stack_trace_save_tsk);
 
 /**
  * stack_trace_save_regs - Save a stack trace based on pt_regs into a storage array
@@ -301,6 +302,7 @@ unsigned int stack_trace_save_tsk(struct task_struct *task,
 	save_stack_trace_tsk(task, &trace);
 	return trace.nr_entries;
 }
+EXPORT_SYMBOL_GPL(stack_trace_save_tsk);
 
 /**
  * stack_trace_save_regs - Save a stack trace based on pt_regs into a storage array