Fix Firmware class name collision

following patch fixes the i2c name collision with i2c-dev.

http://mcentral.de/wiki/index.php/Bugtracker#i2c_core_problem

This issue has been experienced with em28xx and saa7133 based devices.
I discussed that problem with Jean Delvare a while ago and he proposed 
to add a prefix to the class name.
Signed-off-by: NMarkus Rechberger <markus.rechberger@amd.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/base/firmware_class.c

@@ -292,8 +292,7 @@ firmware_class_timeout(u_long data)
 
 static inline void fw_setup_device_id(struct device *f_dev, struct device *dev)
 {
-	/* XXX warning we should watch out for name collisions */
-	strlcpy(f_dev->bus_id, dev->bus_id, BUS_ID_SIZE);
+	snprintf(f_dev->bus_id, BUS_ID_SIZE, "firmware-%s", dev->bus_id);
 }
 
 static int fw_register_device(struct device **dev_p, const char *fw_name,