vl: drop full_screen variable

Not used any more, delete it.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-id: 20180202111022.19269-11-kraxel@redhat.com
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

vl.c

@@ -150,7 +150,6 @@ static int rtc_utc = 1;
 static int rtc_date_offset = -1; /* -1 means no change */
 QEMUClockType rtc_clock;
 int vga_interface_type = VGA_NONE;
-static int full_screen = 0;
 static DisplayOptions dpy;
 int no_frame;
 Chardev *serial_hds[MAX_SERIAL_PORTS];
@@ -3652,7 +3651,6 @@ int main(int argc, char **argv, char **envp)
                 loadvm = optarg;
                 break;
             case QEMU_OPTION_full_screen:
-                full_screen = 1;
                 dpy.has_full_screen = true;
                 dpy.full_screen = true;
                 break;