[CUF] Support fixed size arrays completely

[domcharrier]

GPUFORT can translate the following expressions as
they do not imply that an additional allocation and deallocation
must be generated at the begin and end of the scope.

real, device, allocatable :: x_d(:), y_d(:)

For the same reason, the translation of fixed-size array declarations is not
completely supported.

Hence,

 real, device :: x_d(N), y_d(N)

will simply be translated to

real, device, dimension(:) :: x_d
real, device, dimension(:) :: y_d

Currently, no corresponding hipMalloc and hipFree calls are generated into the code.