spi: spi-imx: complete conversion from master -> controller

With patch:
| 8caab75 ("spi: Generalize SPI "master" to "controller"")
the SPI "master" was generalized to "controller". This patch completed
the conversion of the spi-imx driver by replacing the remaining
occurrences of master to controller.

Signed-off-by: Marc Kleine-Budde <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mark Brown <[email protected]>

Author: marckleinebudde