Input: remove redundant spi driver bus initialization

In ancient times it was necessary to manually initialize the bus field of an
spi_driver to spi_bus_type. These days this is done in spi_driver_register(),
so we can drop the manual assignment.

The patch was generated using the following coccinelle semantic patch:
// <smpl>
@@
identifier _driver;
@@
struct spi_driver _driver = {
	.driver = {
-		.bus = &spi_bus_type,
	},
};
// </smpl>

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/input/touchscreen/ads7846.c

@@ -1426,7 +1426,6 @@ static int __devexit ads7846_remove(struct spi_device *spi)
 static struct spi_driver ads7846_driver = {
 	.driver = {
 		.name	= "ads7846",
-		.bus	= &spi_bus_type,
 		.owner	= THIS_MODULE,
 		.pm	= &ads7846_pm,
 	},