Add self tests (taken from #1549).

Signed-off-by: Pol Henarejos <pol.henarejos@cttc.es>

include/mbedtls/sha3.h

@@ -183,6 +183,17 @@ int mbedtls_sha3( mbedtls_sha3_id id, const uint8_t *input,
                     uint8_t *output,
                     size_t olen );
 
+#if defined(MBEDTLS_SELF_TEST)
+/**
+ * \brief          Checkup routine for the algorithms implemented
+ *                 by this module: SHA3-224, SHA3-256, SHA3-384, SHA3-512,
+ *                 SHAKE128, SHAKE256, cSHAKE128 and cSHAKE256.
+ *
+ * \return         0 if successful, or 1 if the test failed.
+ */
+int mbedtls_sha3_self_test( int verbose );
+#endif /* MBEDTLS_SELF_TEST */
+
 #ifdef __cplusplus
 }
 #endif