checkpatch: allow printk strings to exceed 80 characters to maintain their searchability

Allow printk strings to break the 80 character width limits, thus keeping
them complete and searchable.

Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>