kernel: rename show_stack_loglvl() => show_stack()

Now the last users of show_stack() got converted to use an explicit log
level, show_stack_loglvl() can drop it's redundant suffix and become once
again well known show_stack().

Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200418201944.482088-51-dima@arista.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/tty/sysrq.c

@@ -235,7 +235,7 @@ static void showacpu(void *dummy)
 
 	raw_spin_lock_irqsave(&show_lock, flags);
 	pr_info("CPU%d:\n", smp_processor_id());
-	show_stack_loglvl(NULL, NULL, KERN_INFO);
+	show_stack(NULL, NULL, KERN_INFO);
 	raw_spin_unlock_irqrestore(&show_lock, flags);
 }