[BUG] build problem - about /pppm_dplr.cpp

[pee8379]

Recent version of lammps changes gridcomm.h , (looks like version newer than Jun 10, 2021) remove forward_comm_kspace from file.
Same with reverse_comm_kspace .

Therefore, during installing deepmd-kit c++ interface from source code, /source/lmp/pppm_dplr.cpp make error and crash building process.

[njzjz]

Already fixed in #1129

[njzjz]

Note that this change is in lammps/lammps#2902 which was merged just 15 days ago.