=== Kernel Crypto changes to support WireGuard

Contact: John Baldwin <jhb@FreeBSD.org>

During the last quarter, I continued my work to improve the FreeBSD WireGuard driver.
On the FreeBSD side, I added support for the XChaCha20-Poly1305 AEAD cipher.
I also added a dedicated API to support [X]ChaCha20-Poly1035 on small, flat buffers.
Finally, I added an API wrapper for the curve25519 implementation from libsodium.

For the WireGuard driver, I wrote a series of patches which updates the driver to use crypto APIs such as those mentioned above in place of internal cipher implementations.
The series also includes a fix to avoid scheduling excessive crypto tasks as well as a few other small fixes.
This series is pending review.

Sponsor: The FreeBSD Foundation
