spi/gpio: Fix stub for spi_gpio_probe_dt()

The gpio_ was missing from the name.  Add a name for the parameter while
we're at it since GCC warns.
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

drivers/spi/spi-gpio.c

@@ -386,7 +386,7 @@ static int spi_gpio_probe_dt(struct platform_device *pdev)
 	return ret;
 }
 #else
-static inline int spi_probe_dt(struct platform_device *)
+static inline int spi_gpio_probe_dt(struct platform_device *pdev)
 {
 	return 0;
 }