Add the devicetree bindings documentation for the Analog Devices
axi-spi-engine SPI master peripheral. This is a soft-peripheral used in
FPGAs.
The external interfaces of the peripheral are:
* A memory mapped register map which is used to configure the
peripheral.
* One interrupt.
* Two clocks, one for the memory mapped register interface and one
for the SPI bus.
* A SPI master interface to which the slave devices are connected.
These interfaces are described by the devicetree bindings accordingly.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
