scripts: set proper OpenSSL include dir also for sign-file

stable inclusion
from stable-5.10.17
commit 902c6dcbb146eb119ae539a231103619855df6a0
bugzilla: 48169

--------------------------------

commit fe968c41 upstream.

Fixes: 2cea4a7a ("scripts: use pkg-config to locate libcrypto")
Signed-off-by: Rolf Eike Beer <eb@emlix.com>
Cc: stable@vger.kernel.org # 5.6.x
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>