12638 ntwdt: NULL pointer errors
Reviewed by: Andrew Stormont <andyjstormont@gmail.com>
Approved by: Gordon Ross <gordon.w.ross@gmail.com>

PSARC/2009/396 Tickless Kernel Architecture / lbolt decoupling
6860030 tickless clock requires a clock() decoupled lbolt / lbolt64
Portions contributed by Chad Mynhier <cmynhier@gmail.com>

PSARC 2008/382 Fast Reboot
6714038 Fast Reboot support for x86 platforms

6461636 Watchdog timer should not display messages when disabled
6500505 sun4v backward compatibility ntwdt driver for Niagara based system