lkl: fix print functions to use lkl_ prefixed ones

This fix is useful when the underlying host doesn't have particular
functions (e.g., strerr() and fprintf()) as such in non libc
environment.

Signed-off-by: Hajime Tazaki <thehajime@gmail.com>

tools/lkl/lib/net.c

@@ -381,7 +381,7 @@ static int check_error(struct lkl_sockaddr_nl *nladdr, struct lkl_nlmsghdr *n,
 			return 0;
 
 		lkl_printf("RTNETLINK answers: %s\n",
-			strerror(-err->error));
+			lkl_strerror(-err->error));
 		return err->error;
 	}
 	lkl_printf("Unexpected reply!!!\n");

tools/lkl/lib/utils.c

@@ -155,7 +155,7 @@ void lkl_perror(char *msg, int err)
 	const char *err_msg = lkl_strerror(err);
 	/* We need to use 'real' printf because lkl_host_ops.print can
 	 * be turned off when debugging is off. */
-	fprintf(stderr, "%s: %s\n", msg, err_msg);
+	lkl_printf("%s: %s\n", msg, err_msg);
 }
 
 static int lkl_vprintf(const char *fmt, va_list args)