can: tcan4x5x: tcan4x5x_regmap_init(): use spi as context pointer

This patch replaces the context pointer of the regmap callback functions by a
pointer to the spi_device. This saves one level of indirection in the
callbacks.
Reviewed-by: Dan Murphy <dmurphy@ti.com>
Tested-by: Sean Nyekjaer <sean@geanix.com>
Link: https://lore.kernel.org/r/20201215231746.1132907-11-mkl@pengutronix.deSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/m_can/tcan4x5x-regmap.c

@@ -18,8 +18,7 @@ static int tcan4x5x_regmap_gather_write(void *context, const void *reg,
 					size_t reg_len, const void *val,
 					size_t val_len)
 {
-	struct device *dev = context;
-	struct spi_device *spi = to_spi_device(dev);
+	struct spi_device *spi = context;
 	struct spi_message m;
 	u32 addr;
 	struct spi_transfer t[2] = {
@@ -47,8 +46,7 @@ static int tcan4x5x_regmap_read(void *context,
 				const void *reg, size_t reg_size,
 				void *val, size_t val_size)
 {
-	struct device *dev = context;
-	struct spi_device *spi = to_spi_device(dev);
+	struct spi_device *spi = context;
 
 	u32 addr = TCAN4X5X_READ_CMD | (*((u16 *)reg) << 8) | val_size >> 2;
 
@@ -73,6 +71,6 @@ static const struct regmap_bus tcan4x5x_bus = {
 int tcan4x5x_regmap_init(struct tcan4x5x_priv *priv)
 {
 	priv->regmap = devm_regmap_init(&priv->spi->dev, &tcan4x5x_bus,
-					&priv->spi->dev, &tcan4x5x_regmap);
+					priv->spi, &tcan4x5x_regmap);
 	return PTR_ERR_OR_ZERO(priv->regmap);
 }