[X86] Add cost table entry for v2i32->v2f64 fp_to_uint with avx512.

We're currently getting this from the default implementation. But
I don't like how the cost model came to this answer and I might
be making some changes there.

llvm/lib/Target/X86/X86TargetTransformInfo.cpp

@@ -1610,6 +1610,7 @@ int X86TTIImpl::getCastInstrCost(unsigned Opcode, Type *Dst, Type *Src,
 
     { ISD::FP_TO_UINT,  MVT::v2i32,  MVT::v2f32,  1 },
     { ISD::FP_TO_UINT,  MVT::v4i32,  MVT::v4f32,  1 },
+    { ISD::FP_TO_UINT,  MVT::v2i32,  MVT::v2f64,  1 },
     { ISD::FP_TO_UINT,  MVT::v4i32,  MVT::v4f64,  1 },
     { ISD::FP_TO_UINT,  MVT::v8i32,  MVT::v8f32,  1 },
   };