[mlir][arith][spirv] Add missing fptoui conversion

mlir/lib/Conversion/ArithToSPIRV/ArithToSPIRV.cpp

patterns.add<
     TypeCastingOpPattern<arith::ExtUIOp, spirv::UConvertOp>, ExtUII1Pattern,
     TypeCastingOpPattern<arith::ExtSIOp, spirv::SConvertOp>, ExtSII1Pattern,
     TypeCastingOpPattern<arith::ExtFOp, spirv::FConvertOp>,
     TypeCastingOpPattern<arith::TruncIOp, spirv::SConvertOp>, TruncII1Pattern,
     TypeCastingOpPattern<arith::TruncFOp, spirv::FConvertOp>,
     TypeCastingOpPattern<arith::UIToFPOp, spirv::ConvertUToFOp>, UIToFPI1Pattern,
     TypeCastingOpPattern<arith::SIToFPOp, spirv::ConvertSToFOp>,
     TypeCastingOpPattern<arith::FPToSIOp, spirv::ConvertFToSOp>,
+    TypeCastingOpPattern<arith::FPToUIOp, spirv::ConvertFToUOp>,
     TypeCastingOpPattern<arith::IndexCastOp, spirv::SConvertOp>,
     TypeCastingOpPattern<arith::IndexCastUIOp, spirv::UConvertOp>,
     TypeCastingOpPattern<arith::BitcastOp, spirv::BitcastOp>,
     CmpIOpBooleanPattern, CmpIOpPattern,
     CmpFOpNanNonePattern, CmpFOpPattern,
     AddUIExtendedOpPattern,
     MulIExtendedOpPattern<arith::MulSIExtendedOp, spirv::SMulExtendedOp>,
     MulIExtendedOpPattern<arith::MulUIExtendedOp, spirv::UMulExtendedOp>,

mlir/test/Conversion/ArithToSPIRV/arith-to-spirv.mlir

 
 // CHECK-LABEL: @fptosi2
 func.func @fptosi2(%arg0 : f16) -> i16 {
   // CHECK: spirv.ConvertFToS %{{.*}} : f16 to i16
   %0 = arith.fptosi %arg0 : f16 to i16
   return %0 : i16
 }
 
+// CHECK-LABEL: @fptoui1
+func.func @fptoui1(%arg0 : f32) -> i32 {
+  // CHECK: spirv.ConvertFToU %{{.*}} : f32 to i32
+  %0 = arith.fptoui %arg0 : f32 to i32
+  return %0 : i32
+}
+
+// CHECK-LABEL: @fptoui2
+func.func @fptoui2(%arg0 : f16) -> i16 {
+  // CHECK: spirv.ConvertFToU %{{.*}} : f16 to i16
+  %0 = arith.fptoui %arg0 : f16 to i16
+  return %0 : i16
+}
+
 } // end module
 
 // -----
 
 // Checks that cast types will be adjusted when missing special capabilities for
 // certain non-32-bit scalar types.
 module attributes {
   spirv.target_env = #spirv.target_env<#spirv.vce<v1.0, [Float64], []>, #spirv.resource_limits<>>