i2o: fix overflow of copy_to_user()

If (len > reslen) we must not call copy_to_user() since kernel buffer is
smaller than we want to copy.  Similar code in this file is correct, so
this bug was a typo.

Signed-off-by: Kulikov Vasiliy <segooon@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>