Update L2ARC code and fix several bugs.
- improve ARC memory consumption (Bug ID 6488341)
- ARC/L2ARC metadata accounting (Bug ID 6748019)
- L2ARC turbo warmup (Bud ID 6748023)
- kstats for ARC content (Bug ID 6748023)
- kstats for evicted bytes from ARC by L2ARC state (Bud ID 6871680)
- fix panic on i386 systems (Bug ID 6821260)
OpenSolaris onnv revisions:
8582:df9361868dbe, 8628:97dcded6e556, 9215:7c4584f76b47,
9274:a10f8bd993c1, 10357:29060492b29d
OpenSolaris Bug IDs:
6748019, 6748023, 6748030, 6488341, 6798268, 6821260, 6790261, 6871680
Approved by: pjd, delphij (mentor)
Obtained from: OpenSlaris (multiple bug IDs)
MFC after: 3 days
7838815ebb