[flang][cuda] fix parsing of cuda_kernel (#89613)

Fix parsing of cuda_kernel: it missed a mlir::succeeded check and it was
not setting up the `types` and causing mismatch between values and types
of the grid/block (CUFKernelValues). @clementval

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Co-authored-by: Iman Hosseini <imanh@nvidia.com>
Co-authored-by: Valentin Clement (バレンタイン クレメン) <clementval@gmail.com>