printk: fix typo in CONSOLE_LOGLEVEL_DEFAULT help text

s/prink/printk/

Link: http://lkml.kernel.org/r/20161215170111.19075-1-bp@alien8.de


Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Olof Johansson <olof@lixom.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>