spi: fix spidev compilation failure when VERBOSE is defined

When VERBOSE is defined in the spidev module, the compilation
will throw an error on 'spi' not being defined:

CC [M]  drivers/spi/spidev.o
drivers/spi/spidev.c: In function 'spidev_message':
drivers/spi/spidev.c:266: error: 'spi' undeclared (first use in this function)
drivers/spi/spidev.c:266: error: (Each undeclared identifier is reported only once
drivers/spi/spidev.c:266: error: for each function it appears in.)

instead of using spi-> we should actually use spidev->spi.
This patch fixes the build failure.
Signed-off-by: Florian Fainelli <ffainelli@freebox.fr>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

drivers/spi/spidev.c

@@ -267,15 +267,15 @@ static int spidev_message(struct spidev_data *spidev,
 		k_tmp->delay_usecs = u_tmp->delay_usecs;
 		k_tmp->speed_hz = u_tmp->speed_hz;
 #ifdef VERBOSE
-		dev_dbg(&spi->dev,
+		dev_dbg(&spidev->spi->dev,
 			"  xfer len %zd %s%s%s%dbits %u usec %uHz\n",
 			u_tmp->len,
 			u_tmp->rx_buf ? "rx " : "",
 			u_tmp->tx_buf ? "tx " : "",
 			u_tmp->cs_change ? "cs " : "",
-			u_tmp->bits_per_word ? : spi->bits_per_word,
+			u_tmp->bits_per_word ? : spidev->spi->bits_per_word,
 			u_tmp->delay_usecs,
-			u_tmp->speed_hz ? : spi->max_speed_hz);
+			u_tmp->speed_hz ? : spidev->spi->max_speed_hz);
 #endif
 		spi_message_add_tail(k_tmp, &msg);
 	}