[spirv] Use addNestedPass<FuncOp>() for passes working on functions (#3745)
[spirv] Use addNestedPass<FuncOp>() for passes working on functions (#3745)

This fixes crashes when running the whole pipeline because of pass
manager target op mismatch.
iree-org/iree,iree-org/iree,google/iree,iree-org/iree,google/iree,iree-org/iree,google/iree,iree-org/iree,iree-org/iree,google/iree,google/iree,google/iree,google/iree,iree-org/iree