SMP support for Linux with up to 16 processors using the Intel MP
specification. 

WARNING:
	This is experimental. Back up your disks first. Experience is that
it is basically stable in its current (inefficient form).

To fix:

o	Fix sys_idle to exit/enter kernel state and do hlt's.
o	Fix scheduler decisions to reschedule. Per cpu reschedule ?
o	Clean up message pass.
o	Test for B stepping processors.
o	Clean up processor specific/independent split.
o	Document it all.	[PARTLY DONE]
o	Halt other CPU's on reset/panic doesn't always work.
o	Don't waste page at 4K - don't need it now.(watch the GDT code).
o	Dump bootup pages once booted somehow.
o	Clean up warnings/volatiles.
o	Fix load_TR() for non contiguous processor ids
o	Iterate over the slave timer requests if one is lost (keep a count per cpu)
o	Distribute irq's (locking present just needs the 82489 to be asked
	nicely).
o	486 startup code.
o	How to handle mixed FPU/non FPU processors.