Driver Core: add ability for class_find_device to start in middle of list

This mirrors the functionality that driver_find_device has as well.

We add a start variable, and all callers of the function are fixed up at
the same time.

The block layer will be using this new functionality in a follow-on
patch.


Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 1ad12af..1771b24 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -502,7 +502,7 @@
 	struct device		*dev;
 	struct spi_master	*master = NULL;
 
-	dev = class_find_device(&spi_master_class, &bus_num,
+	dev = class_find_device(&spi_master_class, NULL, &bus_num,
 				__spi_master_match);
 	if (dev)
 		master = container_of(dev, struct spi_master, dev);