Add code that programs the DMA and SSI controllers differently based on the
FIFO depth of the SSI.

The SSI devices on the MPC8610 and the P1022 are identical in every way except
one: the transmit and receive FIFO depth.  On the MPC8610, the depth is eight.
On the P1022, it's fifteen.  The device tree nodes for the SSI include a
"fsl,fifo-depth" property that specifies the FIFO depth.
Signed-off-by: Timur Tabi <timur@freescale.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>