[RISCV][clang] Remove the `zvfhmin` and `zvfh` check for `BaseType` and use `RequiredFeatures` in riscv_vector.td

[4vtomat]

Remove the zvfhmin and zvfh check for BaseType and use RequiredFeatures in riscv_vector.td to check the intrinsics instead, the type check should be done in checkRVVTypeSupport. This check also not able to work on the intrinsics that have Float16 but the BaseType is not Float16 such as vfcvt_f_x_v.

[llvmbot]

@llvm/issue-subscribers-backend-risc-v

Author: Brandon Wu (4vtomat)

Remove the `zvfhmin` and `zvfh` check for `BaseType` and use `RequiredFeatures` in riscv_vector.td to check the intrinsics instead, the type check should be done in `checkRVVTypeSupport`. This check also not able to work on the intrinsics that have `Float16` but the `BaseType` is not Float16 such as `vfcvt_f_x_v`.

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: Brandon Wu (4vtomat)

Remove the `zvfhmin` and `zvfh` check for `BaseType` and use `RequiredFeatures` in riscv_vector.td to check the intrinsics instead, the type check should be done in `checkRVVTypeSupport`. This check also not able to work on the intrinsics that have `Float16` but the `BaseType` is not Float16 such as `vfcvt_f_x_v`.