Lpc2000

There was a lot of discussion about SPI recently, it would be great if
we could summarize how to use it right. For starters this is what I
collected:

- SPI master could not use the select line. SSEL needs to be pulled up
in master mode. If master needs to use select line use a regular GPIO
and drive if from the code.

- There is no FIFO around the SPI.

- There is no receive without sending first in master mode.