winealsa.drv:mmdevapi input validation

[Joerg-Cyril.Hoehle at t-systems.com]

Andrew Eikum wrote: 

>Frankly, I see little reason to spend time implementing special handling
>of exclusive mode unless we find an app that does something that requires it.
Actually, I don't know whether any of the apps I own can use mmdevapi.
I've been looking at it because I believe you are going to rewrite winmm to use it.

>>      if (AUDCLNT_STREAMFLAGS_EVENTCALLBACK&&  SHAREMODE_EXCLUSIVE)
>>         { FIXME("unsupported")&  return E_ }
>Is it really better to outright fail on that combination instead of
>having a (probably quite good) chance at just working?
I fear it's quite low given the precise description that MSDN makes
of the ping pong mode.  That does not happen by chance.

I suppose few apps will depend on exclusive mode because MSDN says
that the user decides whether to grant it or not.  At most, it'll
be an option within an app's menu.

Regards,
 Jörg