x86/dumpstack: Make show_trace_log_lvl() static

show_trace_log_lvl() is not used by other compilation units so make it
static and remove the declaration from the header file.
Signed-off-by: Hui Su <sh_def@163.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20201113133943.GA136221@rlk

arch/x86/include/asm/stacktrace.h

@@ -88,9 +88,6 @@ get_stack_pointer(struct task_struct *task, struct pt_regs *regs)
 	return (unsigned long *)task->thread.sp;
 }
 
-void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
-			unsigned long *stack, const char *log_lvl);
-
 /* The form of the top of the frame on the stack */
 struct stack_frame {
 	struct stack_frame *next_frame;

arch/x86/kernel/dumpstack.c

@@ -168,7 +168,7 @@ static void show_regs_if_on_stack(struct stack_info *info, struct pt_regs *regs,
 	}
 }
 
-void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
+static void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
 			unsigned long *stack, const char *log_lvl)
 {
 	struct unwind_state state;