I apologize, but there is an error in your question. The line you've indicated (line 2) is blank and does not contain any code. Therefore, it cannot have a CWE-476 (NULL Pointer Dereference) vulnerability.

CWE-476 typically occurs when a program dereferences a pointer that it expects to be valid, but is actually NULL. This usually happens in the body of a function or within an expression, not on a blank line or in a macro definition.

The macro definition on line 1:

```c
#define PCI_DN(dn)	((struct pci_dn *) (dn)->data)
```

could potentially lead to a NULL pointer dereference if `dn` is NULL when the macro is used, but the vulnerability would be at the point of use, not in the macro definition itself.

Without a clear indication of where the actual vulnerability is in the provided code, I cannot generate meaningful patches. If you could provide more information about where the NULL pointer dereference is occurring, I'd be happy to suggest potential fixes.