Retire the synchronous character driver protocol

- change all sync char drivers into async drivers;
- retire support for the sync protocol in libchardev;
- remove async dev style, as this is now the default;
- remove dev_status from VFS;
- clean up now-unused protocol messages.

Change-Id: I6aacff712292f6b29f2ccd51bc1e7d7003723e87

drivers/bmp085/bmp085.c

@@ -624,7 +624,7 @@ main(int argc, char *argv[])
 
 	sef_local_startup();
 
-	chardriver_task(&bmp085_tab, CHARDRIVER_SYNC);
+	chardriver_task(&bmp085_tab);
 
 	return 0;
 }