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/xtea.h b/include/mbedtls/xtea.h
index c70c3fe..6430c13 100644
--- a/include/mbedtls/xtea.h
+++ b/include/mbedtls/xtea.h
@@ -37,6 +37,8 @@
#define MBEDTLS_XTEA_DECRYPT 0
#define MBEDTLS_ERR_XTEA_INVALID_INPUT_LENGTH -0x0028 /**< The data input has an invalid length. */
+
+/* MBEDTLS_ERR_XTEA_HW_ACCEL_FAILED is deprecated and should not be used. */
#define MBEDTLS_ERR_XTEA_HW_ACCEL_FAILED -0x0029 /**< XTEA hardware accelerator failed. */
#ifdef __cplusplus