[LegalizeVectorOps][RISCV] Support condition code legalization for...

[LegalizeVectorOps][RISCV] Support condition code legalization for ISD::STRICT_FSETCC/FSETCCS during LegalizeVectorOps.

Switch RISC-V to legalize during LegalizeVectorOps instead of
LegalizeDAG. LegalizeDAG uses the OpVT for legalize action while
LegalizeVectorOps uses the result VT. We really should fix that.