5890 Enable Intel SMEP support when available 5891 want to be able to see x86 control regs with kmdb Reviewed by: Joshua M. Clulow <jmc@joyent.com> Reviewed by: Igor Kozhukhov <ikozhukhov@gmail.com> Reviewed by: Josef 'Jeff' Sipek <josef.sipek@nexenta.com> Approved by: Richard Lowe <richlowe@richlowe.net>