simple SPI controller on PXA2xx SSP port

Following this will be two reposted patches (with whitespace correctly preserved), releasing an initial "SPI controller" implementation running on David Brownell's "simple SPI framework" and a prototype "SPI protocol" driver for the Cirrus Logic CS8415A S/PDIF decoder chip. The controller should run on any PXA2xx SSP port and has been tested on the PXA255 NSSP port. Complete board setup and description facilities per the SPI framework are supported.

Your comments and suggestions encouraged! You can e-mail me directly if you have any question regarding running SPI controller on your board.

Thank you David for helping me make this real!

Stephen Street

"Afflicted by numerous newbie problems"