[winealsa] add support for mixer devices

[Dmitry Timoshkov]

"Maarten Lankhorst" <m.b.lankhorst at gmail.com> wrote:

> +/**************************************************************************
> + *                        mxdMessage (WINEALSA.3)
> + */
> +DWORD WINAPI ALSA_mxdMessage(UINT wDevID, UINT wMsg, DWORD dwUser,
> +                             DWORD dwParam1, DWORD dwParam2)

It would be nice when adding new code make it 64-bit safe from the start,
in this case using a proper DRVCALLBACK prototype for the driver callback,
and using proper data types for passing in/out parameters around.

-- 
Dmitry.