spi/pxa2xx: Add CE4100 support

Sodaville's SPI controller is very much the same as in PXA25x. The
difference:
- The RX/TX FIFO is only 4 words deep instead of 16
- No DMA support
- The SPI controller offers a CS functionality

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Dirk Brandewie <dirk.brandewie@gmail.com>