mbedtls: fix missing mbedtls_time_t bug in mbedtls 2.3.0

This backports a commit from mbedtls current git which adds missing
include for platform.h.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

package/libs/mbedtls/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=mbedtls
 PKG_VERSION:=2.3.0
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 PKG_USE_MIPS16:=0
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION)-gpl.tgz

package/libs/mbedtls/patches/001-Fixes_missing_dependency_in_ssl.patch

@@ -0,0 +1,21 @@
+From 7247f99b3e068a2b90b7776a2cdd438fddb7a38b Mon Sep 17 00:00:00 2001
+From: James Cowgill <james410@cowgill.org.uk>
+Date: Mon, 11 Jul 2016 13:57:05 +0100
+Subject: [PATCH] Fixes missing dependency in ss.h on platform.h
+
+Fixes #522 - 'mbedtls_time_t does not name a type in ssl.h'
+---
+ include/mbedtls/ssl.h | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/include/mbedtls/ssl.h
++++ b/include/mbedtls/ssl.h
+@@ -54,7 +54,7 @@
+ #endif
+ 
+ #if defined(MBEDTLS_HAVE_TIME)
+-#include <time.h>
++#include "platform.h"
+ #endif
+ 
+ /*