mbedtls: Add Copyright and License for reuse compliance

Signed-off-by: Andrei Gherzan <andrei.gherzan@huawei.com>

meta-ohos-foundation/recipes-libs/mbedtls/mbedtls_git.bb

+# SPDX-FileCopyrightText: Huawei Inc.
+#
+# SPDX-License-Identifier: Apache-2.0
+
 SUMMARY = "Mbed TLS"
 DESCRIPTION = "C library for X.509 certificate manipulation and the SSL/TLS and DTLS"
 LICENSE = "Apache-2.0"