Fix typo
previously the variable was mistyped as _CUDA, but the typo was without
consequences because the _CUDA variable was defined by default what
cuda Fortran was enabled. New versions of nvidia cmpiler do not define the
variable any more
previously the variable was mistyped as _CUDA, but the typo was without
consequences because the _CUDA variable was defined by default what
cuda Fortran was enabled. New versions of nvidia cmpiler do not define the
variable any more