Enabled mbed TLS to use nsdynmemlib on simulator

If MBEDTLS_PLATFORM_MEMORY is enabled, Wi-SUN mbed TLS uses now
nsdynmemlib for memory allocations. Currently platform memory
is enabled only on simulator.

Author: Mika Leppänen

source/Security/protocols/tls_sec_prot/tls_sec_prot_lib.c

@@ -106,12 +106,11 @@ int8_t tls_sec_prot_lib_init(tls_security_t *sec)
     const char *pers = "ws_tls";
 
 #ifdef MBEDTLS_PLATFORM_MEMORY
-    (void) tls_sec_prot_lib_mem_calloc;
-    (void) tls_sec_prot_lib_mem_free;
-    // Disabled for now
-    //mbedtls_platform_set_calloc_free(tls_sec_prot_lib_mem_calloc, tls_sec_prot_lib_mem_free);
+    // Enabled if platform memory is enabled
+    mbedtls_platform_set_calloc_free(tls_sec_prot_lib_mem_calloc, tls_sec_prot_lib_mem_free);
 #endif
 
+
     mbedtls_ssl_init(&sec->ssl);
     mbedtls_ssl_config_init(&sec->conf);
     mbedtls_ctr_drbg_init(&sec->ctr_drbg);