Use a static callout to drive key_timehandler() instead of timeout().
While here, make key_timehandler() private to key.c.

Submitted by:	bz (2)
Tested by:	bz
Under PAE ULONG is insufficient for representing the physical memory size.  Use QUAD
for "hw.physmem" so that a physical memory size greater than 4 GB can be specified
from the boot loader.