sys: Automated cleanup of cdefs and other formatting

Apply the following automated changes to try to eliminate
no-longer-needed sys/cdefs.h includes as well as now-empty
blank lines in a row.

Remove /^#if.*\n#endif.*\n#include\s+<sys/cdefs.h>.*\n/
Remove /\n+#include\s+<sys/cdefs.h>.*\n+#if.*\n#endif.*\n+/
Remove /\n+#if.*\n#endif.*\n+/
Remove /^#if.*\n#endif.*\n/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/types.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/param.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/capsicum.h>/

Sponsored by: Netflix

sys: Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

xform_*.c: Add headers when needed to compile standalone.

Reviewed by: markj
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D33994

crypto: Re-add encrypt/decrypt_multi hooks to enc_xform.

These callbacks allow multiple contiguous blocks to be manipulated in
a single call. Note that any trailing partial block for a stream
cipher must still be passed to encrypt/decrypt_last.

While here, document the setkey and reinit hooks and reorder the hooks
in 'struct enc_xform' to better reflect the life cycle.

Reviewed by: markj
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D33529

crypto: Move CBC handling into enc_xform_aes_cbc.

Add an IV to the context that is initialized by the reinit hook.
Encrypt and decrypt operations handle cipher block chaining along with
updating the IV saved in the context.

Reviewed by: markj
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D33487

crypto: Consistently use AES instead of Rijndael128 for the AES-CBC cipher.

Reviewed by: markj
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D33486