include/asm/offset.h is a generated file on x86_64 and mips.  Let's add it
to Documentation/dontdiff.
Signed-off-by: NMichal Schmidt <xschmi00@stud.feec.vutbr.cz>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>