feat(riscv64): Support RISC-V Zfa extension

* Support fli.{h.s.d}, fminm.{h.s.d}, fmaxm.{h.s.d}
* Support fround.{h.s.d}, froundnx.{h.s.d}, fcvtmod.w.d
* Support fleq.{h.s.d}, fltq.{h.s.d}