fbdev/core: Disable console-lock warnings when fb.lockless_register_fb is set

If the console is unlocked during registration, the console subsystem
generates significant amounts of warnings, which obfuscate actual
debugging messages. Setting ignore_console_lock_warning while debugging
console registration avoid the noise.

v3:
	- manipulate ignore_console_lock_warning with atomic_{inc,dec}
v2:
	- restore ignore_console_lock_warning if lock_fb_info() fails
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

drivers/video/fbdev/core/fbmem.c

@@ -1690,17 +1690,22 @@ static int do_register_framebuffer(struct fb_info *fb_info)
 	event.info = fb_info;
 	if (!lockless_register_fb)
 		console_lock();
+	else
+		atomic_inc(&ignore_console_lock_warning);
 	if (!lock_fb_info(fb_info)) {
-		if (!lockless_register_fb)
-			console_unlock();
-		return -ENODEV;
+		ret = -ENODEV;
+		goto unlock_console;
 	}
+	ret = 0;
 
 	fb_notifier_call_chain(FB_EVENT_FB_REGISTERED, &event);
 	unlock_fb_info(fb_info);
+unlock_console:
 	if (!lockless_register_fb)
 		console_unlock();
-	return 0;
+	else
+		atomic_dec(&ignore_console_lock_warning);
+	return ret;
 }
 
 static int unbind_console(struct fb_info *fb_info)