Annotate the rest of X86InstrInfo.td with SchedRW lists.
Annotate control instructions with SchedRW lists.

This could definitely be more granular. I am not sure if it makes a
difference.
Annotate x87 and mmx instructions with SchedRW lists.

This only covers the instructions that were given itinerary classes for
the Atom model.
Annotate the remaining x86 instructions with SchedRW lists.

Now all x86 instructions that have itinerary classes also have SchedRW
lists. This is required before the new scheduling models can be used.

There are still unannotated instructions remaining, but they don't have
itinerary classes either.