cryptocheck: Add Chacha20-Poly1305 AEAD coverage.

• Make openssl_gcm_encrypt generic to AEAD ciphers (aside from CCM) and use it for Chacha20-Poly1305.

• Use generic AEAD control constants instead of GCM/CCM specific names.

Reviewed by: cem
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D27838