checkpatch: variants -- move the main unary/binary operators to use variants

Now that we have a variants system, move to using that to carry the
unary/binary designation for +, -, &, and *.

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>