user32: avoid NULL pointer access in DefWindowProcA WM_NCCREATE

[Felix Nawothnig]

Jan Zerebecki wrote:
>              CREATESTRUCTA *cs = (CREATESTRUCTA *)lParam;
>              /* check for string, as static icons, bitmaps (SS_ICON, SS_BITMAP)
>               * may have child window IDs instead of window name */
> -            if (HIWORD(cs->lpszName))
> +            if (cs && HIWORD(cs->lpszName))

cs is never NULL at that point.

Felix