Adjustments to the "earlyentropy" branch in response to the various
discussions beginning with my initial proposal
http://mail-index.netbsd.org/tech-kern/2014/04/08/msg016876.html and
particularly the long discussion of cprng_fast() performance (e.g.
https://mail-index.netbsd.org/tech-crypto/2014/04/21/msg000642.html).

In particular:

	* Per-CPU, lockless cprng_fast replacement using Dennis Ferguson's
	  "ccrand" implementation of ChaCha8.

	* libkern arc4random() is gone, gone, gone.

	* Entropy estimator reverted to 32-bit recordkeeping and timestamps
	  per Dennis' comments and analysis.

	* LZF entropy estimator removed: it required a great deal of state,
	  and rejected only truly pathological input.

	I have not yet reverted the changes that provide LZF in the kernel
	as generic functionality; I will likely revert those changes prior
	to any merge of this branch to HEAD.