Remove hmac_sha256 from public API (#2519)

Co-authored-by: あく <alleteam@gmail.com>

applications/main/u2f/hmac_sha256.h

@@ -0,0 +1,38 @@
+#pragma once
+
+#include "sha256.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct hmac_context {
+    void (*init_hash)(const struct hmac_context* context);
+    void (*update_hash)(
+        const struct hmac_context* context,
+        const uint8_t* message,
+        unsigned message_size);
+    void (*finish_hash)(const struct hmac_context* context, uint8_t* hash_result);
+    unsigned block_size; /* Hash function block size in bytes, eg 64 for SHA-256. */
+    unsigned result_size; /* Hash function result size in bytes, eg 32 for SHA-256. */
+    uint8_t* tmp; /* Must point to a buffer of at least (2 * result_size + block_size) bytes. */
+} hmac_context;
+
+typedef struct hmac_sha256_context {
+    hmac_context hmac_ctx;
+    sha256_context sha_ctx;
+    uint8_t tmp[32 * 2 + 64];
+} hmac_sha256_context;
+
+void hmac_sha256_init(hmac_sha256_context* ctx, const uint8_t* K);
+
+void hmac_sha256_update(
+    const hmac_sha256_context* ctx,
+    const uint8_t* message,
+    unsigned message_size);
+
+void hmac_sha256_finish(const hmac_sha256_context* ctx, const uint8_t* K, uint8_t* hash_result);
+
+#ifdef __cplusplus
+}
+#endif