afalg_engine: remove

afalg_engine: remove

Because AI bots are shredding through the AF_ALG code in the kernel,
upstream has decided to deprecate AF_ALG:

https://lore.kernel.org/all/20260430011544.31823-1-ebiggers@kernel.org/

Follow their lead and do the same here.

afalg_engine AFAIK is a faster version of what OpenSSL provides last
time I used it. Although I don't think it was useful for long. OpenSSH's
sandbox conflicts with AF_ALG.

Signed-off-by: Rosen Penev <redacted>