environment variable which can set to "100", "133", or "150". The
CPU clock will be configured accordingly upon next reboot. Other
values are ignored. In case of an invalid or undefined "cpuclk"
value, the compile-time default CPU clock speed will be used.
* Enable Quad-UART on BMS2003 board (initialize the PCMCIA memory
window that is used to access the UART registers by the Linux driver)
* Patch by Reinhard Meyer, 20 Dec 2003:
Fix clock calculation for the MPC5200 for higher clock frequencies
(above 2**32 / 10 = 429.5 MHz).
wdenk