[mlir][gpu] Allow all dialects in SCF to GPU conversion.

With the standard dialect being split up, the set of dialects that are
used when converting to GPU is growing. This change modifies the
SCFToGpu pass to allow all operations inside launch bodies.

Differential Revision: https://reviews.llvm.org/D96480

mlir/lib/Conversion/SCFToGPU/SCFToGPUPass.cpp

@@ -50,9 +50,7 @@ struct ParallelLoopToGpuPass
     OwningRewritePatternList patterns;
     populateParallelLoopToGPUPatterns(patterns, &getContext());
     ConversionTarget target(getContext());
-    target.addLegalDialect<AffineDialect, complex::ComplexDialect,
-                           gpu::GPUDialect, scf::SCFDialect,
-                           StandardOpsDialect>();
+    target.markUnknownOpDynamicallyLegal([](Operation *) { return true; });
     configureParallelLoopToGPULegality(target);
     if (failed(applyPartialConversion(getOperation(), target,
                                       std::move(patterns))))