axtls: Additional header files for building axTLS

MicroPython overrides the axTLS port configuration file, but fails
to include <arpa/inet.h> (needed for htonl) and <sys/time.h>
(needed for gettimeofday).  This results in build failures with
compilers which do not support implicit function declarations
(which were removed from C in 1999).

Submitted upstream: <https://github.com/micropython/micropython/pull/10203>

diff --git micropython-1.19.1/extmod/axtls-include/axtls_os_port.h micropython-1.19.1/extmod/axtls-include/axtls_os_port.h
index ef2683acfc7016b5..b9a6ffe56cf121e5 100644
--- micropython-1.19.1/extmod/axtls-include/axtls_os_port.h
+++ micropython-1.19.1/extmod/axtls-include/axtls_os_port.h
@@ -26,7 +26,9 @@
 #ifndef AXTLS_OS_PORT_H
 #define AXTLS_OS_PORT_H
 
+#include <arpa/inet.h>
 #include <errno.h>
+#include <sys/time.h>
 #include "py/stream.h"
 #include "lib/crypto-algorithms/sha256.h"