When running test 5 in Memtest86+ v1.65, I got a "this opcode is not

When running test 5 in Memtest86+ v1.65, I got a "this opcode is not
supported", so I decided to add it. It's a compare operation, and it's
just the opposite of the already supported one (opcode 0x39), so it's
nothing spectacular. Why there's a page-fault when this instruction gets
executed, I haven't got a clue, but I have a feeling that Memtest86 is
doing something wrong :-( However, this fix may help some other code to
run too...

With this, Test 5 passes all the way through without crashing. I did see
some occassional memory errors in some other tests, and I'm not 100%
sure whether those are caused by the system or they are "real" memory
errors. At some time in the future I may get round to memory testing my
target system...

Signed off by: Mats Petersson (mats.petersson@amd.com).=20