[Bug 56305] CryptEnumProviders doesn't set pdwProvType when szProvName is NULL

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=56305

--- Comment #1 from Dmitry Klionsky  ---
The whole point of this call

```
CryptEnumProviders(dwIndex, NULL, 0, &dwType, NULL, &cbName);
```

is to iterate over all providers looking for a specific dwType.