llvm 19.1.7: not yet implemented: intrinsic: REAL(KIND=2) in SPACING

Trying to build hdf5 1.14.6 with llvm 19.1.7, I get this error:

```
error: loc("/hdf5-1.14.6/fortran/test/tf_gen.F90":209:5):
/llvm-project-19.1.7.src/flang/include/flang/Optimizer/Support/Utils.h:143:
not yet implemented: intrinsic: REAL(KIND=2) in SPACING
LLVM ERROR: aborting
make[2]: *** [Makefile:1068: tf_gen.lo] Error 1
```

This is opened on the llvm side: https://github.com/llvm/llvm-project/issues/83894

With llvm 20 I see another error: https://github.com/HDFGroup/hdf5/issues/5625, so not sure if this error has been solved in llvm 20 or not.