Fix 'infinite' loop in qemu using i8254

	This driver is still disfunctional.

kernel/i8254.s:
	fix printing the link speed.
Doc updates for running QEmu+networking in Linux.

.tcshrc:
	use switch to determine the environment and use different aliases.

DOC/QEMU-Linux.txt:
	document requirements and config to use QEMU with a bridged tap device.

kernel/pci.s:
	added some pci vendor/device id's found when running in linux.