spi: spi-imx: remove unused struct spi_imx_devtype_data::disable_dma callback

In commit 7a908832 ("spi: imx: add fallback feature") the last
user of the struct spi_imx_devtype_data::disable_dma callback was
removed. However the disable_dma member of struct spi_imx_devtype_data
and the callback itself was not removed.

Remove struct spi_imx_devtype_data::disable_dma and mx51_disable_dma()
as they are unused.

Cc: Robin Gong <yibin.gong@nxp.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Link: https://lore.kernel.org/r/20221021131051.1777984-1-mkl@pengutronix.deSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-imx.c

@@ -77,7 +77,6 @@ struct spi_imx_devtype_data {
 	void (*reset)(struct spi_imx_data *spi_imx);
 	void (*setup_wml)(struct spi_imx_data *spi_imx);
 	void (*disable)(struct spi_imx_data *spi_imx);
-	void (*disable_dma)(struct spi_imx_data *spi_imx);
 	bool has_dmamode;
 	bool has_slavemode;
 	unsigned int fifo_size;
@@ -497,11 +496,6 @@ static void mx51_ecspi_trigger(struct spi_imx_data *spi_imx)
 	writel(reg, spi_imx->base + MX51_ECSPI_CTRL);
 }
 
-static void mx51_disable_dma(struct spi_imx_data *spi_imx)
-{
-	writel(0, spi_imx->base + MX51_ECSPI_DMA);
-}
-
 static void mx51_ecspi_disable(struct spi_imx_data *spi_imx)
 {
 	u32 ctrl;
@@ -1043,7 +1037,6 @@ static struct spi_imx_devtype_data imx51_ecspi_devtype_data = {
 	.rx_available = mx51_ecspi_rx_available,
 	.reset = mx51_ecspi_reset,
 	.setup_wml = mx51_setup_wml,
-	.disable_dma = mx51_disable_dma,
 	.fifo_size = 64,
 	.has_dmamode = true,
 	.dynamic_burst = true,
@@ -1058,7 +1051,6 @@ static struct spi_imx_devtype_data imx53_ecspi_devtype_data = {
 	.prepare_transfer = mx51_ecspi_prepare_transfer,
 	.trigger = mx51_ecspi_trigger,
 	.rx_available = mx51_ecspi_rx_available,
-	.disable_dma = mx51_disable_dma,
 	.reset = mx51_ecspi_reset,
 	.fifo_size = 64,
 	.has_dmamode = true,