sdvx: prevent the game from trying a random ASIO driver (#488)

## Link to GitHub Issue, if one exists
n/a

## Description of change
SDVX EG final started to pick an ASIO driver at random and tries to open
it, which causes crashes / hangs if the driver is not compatible
(ASIO4ALL in particular)

Only allow the game to access `HKLM\SOFTWARE\ASIO` if the user has a
Xonar AE, or if ASIO was configured using -sdvxasio.

## Testing
Tested year 1 data and EG final.

src/spice2x/games/sdvx/sdvx.h

@@ -39,5 +39,6 @@ namespace games::sdvx {
         // not depend on the fact that SDVX module is active (since it can be
         // inactive on cabs or partial I/O setup)
         bool VALKYRIE_MODEL = false;
+        void detect_sound_output_device();
     };
 }