winecoreaudio: Fix AudioRenderClient Get/ReleaseBuffer protocol.

Hi,

what happened to this patch?

There are already 2 bug reports about crashes in ReleaseBuffer that may be cured by this, even though
the underlying problem is #28093 (GetCurrentPadding would not return "buffer full" on
native, so the SW would not attempt to Release 0 bytes which causes winecoreaudio to barf).
> - This->getbuf_last = TRUE;
> - This->getbuf_last = 1;

I've nothing to change here for the time being.  IIRC I have a fix for Capture ordering in my
Mac queue, but that is waiting for more tests on capture mode.

(FWIW, I prefer reminders than resend patches still visible in the source/patches/ list.)

Regards,
        Jörg Höhle