spi: spi-cadence: Switch to spi_controller structure

Replace spi_master structure with spi_controller structure.
spi_controller structure provides interface support for
both SPI master and slave controller.
Signed-off-by: Srinivas Goud <srinivas.goud@amd.com>
Link: https://lore.kernel.org/r/1681825625-10265-2-git-send-email-srinivas.goud@amd.comSigned-off-by: Mark Brown <broonie@kernel.org>