Pull printk updates from Petr Mladek:
- Check all mandatory callbacks when registering nbcon consoles
- Fix some compiler warnings
* tag 'printk-for-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
vsnprintf: drop __printf() attributes on binary printing functions
printf: convert test_hashed into macro
printk: nbcon: Check for device_{lock,unlock} callbacks