crypto: Provide a routine to reset cryptops after EAGAIN

[markj]

Summary

Some consumers handle EAGAIN properly, some do not. Rather than
requiring all consumers to fiddle with crypto fields before retrying an
operating, provide a subroutine to do it.

Use it in GELI, which wasn't clearing CRYPTO_F_DONE before retrying.

[jhb]

I think there's also some code in kgssapi/ that should be updated as well?

[jhb]

(Also, probably add to crypto_request.9?)

[markj]

• Update the crypto_request man page
• Add missing calls kgssapi and ipsec

[pauamma_gundo.com]

One minor nit that can be fixed at commit.

share/man/man9/crypto_request.9

147

No comma for a 2-item list.

[jhb]

sys/opencrypto/crypto.c

1758