spi: spi-gpio: fix compilation warning on 64 bits systems

SPI_GPIO_NO_MOSI and SPI_GPIO_NO_MISO flags are type casted to unsigned
long, yet, they are to be stored in an unsigned int field in the
spi_gpio_platform_data structure.

This leads to the following warning during compilation on 64 bits systems:
warning: large integer implicitly truncated to unsigned type [-Woverflow]

Signed-off-by: Maxime Ripard <[e-mail]>
Reported-by: Fengguang Wu <[e-mail]>
Signed-off-by: Mark Brown <[e-mail]>

include/linux/spi/spi_gpio.h

···
  */
 struct spi_gpio_platform_data {
 	unsigned	sck;
-	unsigned	mosi;
-	unsigned	miso;
+	unsigned long	mosi;
+	unsigned long	miso;
 
 	u16		num_chipselect;
 };