This patch adds in support for the DS570 IP.

It's register compatible with the DS464, but adds support for 8/16/32 SPI.

The 8/16/32 support is added by attaching callbacks reading/writing the
proper amount of data. To indicate to the driver which amount of bits
to use a new field is introduced in the platform data struct.
Acked-by: NGrant Likely <grant.likely@secretlab.ca>
Tested-by: NJohn Linn <John.Linn@xilinx.com>
Signed-off-by: NRichard Röjfors <richard.rojfors@mocean-labs.com>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

This patch changes the out_(be)(8|16|32) and in_(be)(8|16|32) calls to 32 bits ioread/iowrite.

The read and write function are attached to the internal struct as callbacks, callback
is selected depending on endianess.

This will also build on platforms not supporting the in/out calls for instance x86.
Acked-by: NGrant Likely <grant.likely@secretlab.ca>
Tested-by: NJohn Linn <John.Linn@xilinx.com>
Signed-off-by: NRichard Röjfors <richard.rojfors@mocean-labs.com>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

This patch splits the xilinx_spi driver into a generic part and a
OF driver part.

The reason for this is to later add in a platform driver as well.
Tested-by: NJohn Linn <John.Linn@xilinx.com>
Signed-off-by: NRichard Röjfors <richard.rojfors@mocean-labs.com>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>