[Clang][LoongArch] Pass "f" and "d" features to cc1 to enable hard float

On LoongArch, currently neither of "f" and "d" feature is passed from
clang driver to cc1 by default. This means the backend generates code
for soft float.

In order to run programs in current LoongArch machines (hard float
environment) this patch temporarily enables "f" and "d" features.

In future, we should conditionally turn on these features depend on
various clang options, e.g. -mdouble-float, -msingle-float,
-msoft-float and -mfpu.