Deprecate hardware acceleration errors
Deprecate the module-specific XXX_HW_ACCEL_FAILED and
XXX_FEATURE_UNAVAILABLE errors, as alternative implementations should now
return `MBEDTLS_ERR_PLATFORM_HW_FAILED` and
`MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED`.
diff --git a/include/mbedtls/cipher.h b/include/mbedtls/cipher.h
index dfb1541..58a5d63 100644
--- a/include/mbedtls/cipher.h
+++ b/include/mbedtls/cipher.h
@@ -62,6 +62,8 @@
#define MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED -0x6280 /**< Decryption of block requires a full block. */
#define MBEDTLS_ERR_CIPHER_AUTH_FAILED -0x6300 /**< Authentication failed (for AEAD modes). */
#define MBEDTLS_ERR_CIPHER_INVALID_CONTEXT -0x6380 /**< The context is invalid. For example, because it was freed. */
+
+/* MBEDTLS_ERR_CIPHER_HW_ACCEL_FAILED is deprecated and should not be used. */
#define MBEDTLS_ERR_CIPHER_HW_ACCEL_FAILED -0x6400 /**< Cipher hardware accelerator failed. */
#define MBEDTLS_CIPHER_VARIABLE_IV_LEN 0x01 /**< Cipher accepts IVs of variable length. */