winmm: RegQueryValueExW wants the size in bytes, not the size in characters.

dlls/winmm/playsound.c

@@ -140,7 +140,7 @@ static HMMIO	get_mmioFromProfile(UINT uFlags, LPCWSTR lpszName)
         if (err != 0)
             goto none;
     }
-    count = sizeof(str)/sizeof(str[0]);
+    count = sizeof(str);
     err = RegQueryValueExW(hSnd, NULL, 0, &type, (LPBYTE)str, &count);
     RegCloseKey(hSnd);
     if (err != 0 || !*str) goto none;