Added field noResults to Instruction.

Added field noResults to Instruction.
Currently tblgen cannot tell which operands in the operand list are results so
it assumes the first one is a result. This is bad. Ideally we would fix this
by separating results from inputs, e.g. (res R32:$dst),
(ops R32:$src1, R32:$src2). But that's a more distruptive change. Adding
'let noResults = 1' is the workaround to tell tblgen that the instruction does
not produces a result. It works for now since tblgen does not support
instructions which produce multiple results.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@25017 91177308-0d34-0410-b5e6-96231b3b80d8