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>