spi: octeon: Remove struct octeon_spi_setup usage

Current code uses struct octeon_spi_setup to store max_speed_hz, chip_select and
mode settings of current spi device.
We can always get the same settings in octeon_spi_do_transfer() by msg->spi.
So this patch removes struct octeon_spi_setup and octeon_spi_setup,
octeon_spi_cleanup functions.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@linaro.org>