Start to add the LLVM builtins to the mips16 exclusion lists for fp.

Start to add the LLVM builtins to the mips16 exclusion lists for fp.
I need to add the rest of these to the list or else to delay putting
out the actual stub until later in code generation when I know if
the external function ever got emitted

Resubmit this patch. The target triple needs to be added to the test so that
clang does not tell the backend the wrong target when the host is BSD. There
is a clang bug in here somewhere that I need to track down. At Mips this
has been filed internally as a bug.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189186 91177308-0d34-0410-b5e6-96231b3b80d8