Driver for the Apple System Management Console (SMC). This hardware is

Driver for the Apple System Management Console (SMC). This hardware is
present on the MacBook, MacBook Pro, and Intel MacMini.

This driver exports information via sysctl in its private sysctl tree
dev.asmc.*. You can get information about temperatures, fan speeds, the
keyboard light sensor and the Sudden Motion Sensor (SMS).
The SMS is very useful to park the disk heads when the laptop is
moved. Basically, the SMS is setup so that, under movement, we get an
interrupt on irq 6 and a devd notification is sent.

Sponsored by:	 Google Summer of Code 2007
Approved by:	 njl (mentor)
Reviewed by:	 attilio (previous version, but very similar), jhb (interrupt
	 	 specific review)