Start to add the builtind to the mips16 exclusion lists for fp.

Start to add the builtind 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189161 91177308-0d34-0410-b5e6-96231b3b80d8