[WATCHDOG] doc: watchdog simple example: don't fail on fsync()

Don't terminate the watchdog daemon when fsync() fails because no
watchdog driver actually implements the fsync() syscall.

Signed-off-by: Giel van Schijndel <[e-mail]>
Signed-off-by: Wim Van Sebroeck <[e-mail]>

Documentation/watchdog/src/watchdog-simple.c

···
 			ret = -1;
 			break;
 		}
-		ret = fsync(fd);
-		if (ret)
-			break;
 		sleep(10);
 	}
 	close(fd);