Patch by Steven Scholz, 16 Aug 2004:

- Introducing the concept of SoCs "./cpu/$(CPU)/$(SOC)"
- creating subdirs for SoCs ./cpu/arm920t/imx and ./cpu/arm920t/s3c24x0
- moving SoC specific code out of cpu/arm920t/ into cpu/arm920t/$(SOC)/
- moving drivers/s3c24x0_i2c.c and drivers/serial_imx.c out of drivers/
  into cpu/arm920t/$(SOC)/