Intel fftw mpi update for MKL >= 11.1

Well, because It is compiled with Intel compiler. (it could be compiled with gnu as well). I made simpilied this here. Anyway I am wondering that don't we have a toolchain with gcc and imkl?
Right now this block does not care about GCC, see the line

55/68 fftw_libs = ["fftw3xc_intel%s" % fftwsuff]