cufftMpAttachComm is deprecated from cuFFTMp 11.4.0

[ia267]

Currently cufftMpAttachComm is used to determine whether we can use cufftMp. However, this is deprecated from 11.40 (see https://docs.nvidia.com/cuda/cufftmp/usage/differences.html). Instead it's recommended to use cufftMpMakePlan2d, cufftMpMakePlan3d, or cufftMpMakePlanDecomposition https://docs.nvidia.com/cuda/cufftmp/release_notes.html

This should be a straight-forward fix:

if (use_cufftmp) then
      ! Try to create cuFFTMp plan (combines MPI attach and plan creation)
      ierr = cufftMpMakePlan3d(plan, MPI_COMM_WORLD, nz, ny, nx, plan_type, worksize)
      if (ierr /= 0) then
        if (is_root) then
          print *, 'cuFFTMp: Plan creation failed (error ', ierr, ')'
          print *, 'Falling back to single-GPU cuFFT'
        end if
        cufftmp_failed = .true.
        use_cufftmp = .false.
        ierr = cufftDestroy(plan)
        ierr = cufftCreate(plan)
      end if
 end if

[ia267]

When calling cufftMpMakePlan3d(...) fails to compile with this error:
NVFORTRAN-S-0038-Symbol, cufftmpmakeplan3d, has not been explicitly declared.

Root cause: in cuFFTMp (CUDA 12.8 / HPC-SDK 25.3), cufftMpMakePlan3d is provided as an inline helper in cufftMp.h (C header), not as a Fortran-exposed API symbol/interface. cufftMpMakePlan3d is not directly callable from Fortran without a C wrapper.

For now we have to use cufftMpAttachComm until they update the Fortran API.