mips tree changes

[Bruce M. Simpson]

I just checked in the basic Sentry5 stuff to p4 mips2. Have fun. The 
real Broadcom support code needs to be ported to NEWBUS, to discover 
onboard peripherals using the Sonics SiliconBackplane. This looks like a 
PCI bus but is subtly different. It does however contain SB-to-PCI 
bridge controllers.

On the WGT634U there is an EHCI USB2 chip on the PCI bus and a minipci 
slot which usually contains an Atheros 5212.

I have made a change to the Malta config to try to calibrate the clock 
based on the on-chip counter using the RTC. You can turn this off by 
commenting out the kernel option TICK_USE_MALTA_RTC, it slows kernel 
startup in gxemul down slightly.

BMS