R600/SI: Add FP mode bits to binary.

The default rounding mode to initialize the mode register needs
to be reported to the runtime. Fill in other bits a kernel
may be interested in setting for future use.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211791 91177308-0d34-0410-b5e6-96231b3b80d8