spice-char: remove unused field

Signed-off-by: NMarc-André Lureau <marcandre.lureau@gmail.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

spice-qemu-char.c

@@ -11,7 +11,6 @@
 typedef struct SpiceCharDriver {
     CharDriverState*      chr;
     SpiceCharDeviceInstance     sin;
-    char                  *subtype;
     bool                  active;
     bool                  blocked;
     const uint8_t         *datapos;