spi: loopback-test: Follow renaming of SPI "master" to "controller"

In commit 8caab75f ("spi: Generalize SPI "master" to "controller"")
some functions and struct members were renamed. To not break all drivers
compatibility macros were provided.

To be able to remove these compatibility macros push the renaming into
this driver.
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/2f57c89d601d0875cd245a2e95c915b9bfcfc47d.1707324794.git.u.kleine-koenig@pengutronix.deSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-loopback-test.c

@@ -1031,8 +1031,8 @@ int spi_test_run_test(struct spi_device *spi, const struct spi_test *test,
 #define FOR_EACH_ALIGNMENT(var)						\
 	for (var = 0;							\
 	    var < (test->iterate_##var ?				\
-			(spi->master->dma_alignment ?			\
-			 spi->master->dma_alignment :			\
+			(spi->controller->dma_alignment ?		\
+			 spi->controller->dma_alignment :		\
 			 test->iterate_##var) :				\
 			1);						\
 	    var++)