This patch introduces the CAIF SPI Protocol Driver for
CAIF Link Layer.

This driver implements a platform driver to accommodate for a
platform specific SPI device. A general platform driver is not
possible as there are no SPI Slave side Kernel API defined.
A sample CAIF SPI Platform device can be found in
.../Documentation/networking/caif/spi_porting.txt
Signed-off-by: NSjur Braendeland <sjur.brandeland@stericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>