should be done in crypto_done rather than in the callback thread
o use this flag to mark operations from /dev/crypto since the callback
routine just does a wakeup; this eliminates the last unneeded ctx switch
o change CRYPTO_F_NODELAY to CRYPTO_F_BATCH with an inverted meaning
so "0" becomes the default/desired setting (needed for user-mode
compatibility with openbsd)
o change crypto_dispatch to honor CRYPTO_F_BATCH instead of always
dispatching immediately
o remove uses of CRYPTO_F_NODELAY
o define COP_F_BATCH for ops submitted through /dev/crypto and pass
this on to the op that is submitted
Similar changes and more eventually coming for asymmetric ops.
MFC if re gives approval.