Update IDF to a0468b2 (#2108)

* Update IDF to a0468b2

* add missing ld file

* Fix PIO builds and change coex policy

tools/sdk/include/mbedtls/sha256_alt.h

@@ -0,0 +1,57 @@
+/*
+ *  SHA-256 implementation with hardware ESP32 support added.
+ *  Uses mbedTLS software implementation for failover when concurrent
+ *  SHA operations are in use.
+ *
+ *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
+ *  Additions Copyright (C) 2016, Espressif Systems (Shanghai) PTE LTD
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may
+ *  not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ */
+#ifndef _SHA256_ALT_H_
+#define _SHA256_ALT_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if defined(MBEDTLS_SHA256_ALT)
+
+typedef enum {
+    ESP_MBEDTLS_SHA256_UNUSED, /* first block hasn't been processed yet */
+    ESP_MBEDTLS_SHA256_HARDWARE, /* using hardware SHA engine */
+    ESP_MBEDTLS_SHA256_SOFTWARE, /* using software SHA */
+} esp_mbedtls_sha256_mode;
+
+/**
+ * \brief          SHA-256 context structure
+ */
+typedef struct
+{
+    uint32_t total[2];          /*!< number of bytes processed  */
+    uint32_t state[8];          /*!< intermediate digest state  */
+    unsigned char buffer[64];   /*!< data block being processed */
+    int is224;                  /*!< 0 => SHA-256, else SHA-224 */
+    esp_mbedtls_sha256_mode mode;
+}
+mbedtls_sha256_context;
+
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif