[ARM] Add support for -sp- FPUs and FPU none to TargetParser

These are added mainly for the benefit of clang, but this also means that they
are now allowed in .fpu directives and we emit the correct .fpu directive when
single-precision-only is used.

Differential Revision: http://reviews.llvm.org/D10238

llvm-svn: 239151
GitOrigin-RevId: 985c04e8fafb2489b1fa960ebba5383e9d77e91e
6 files changed