Add the product id to the driver model platform device name, in addition to
the device id.  The IPMI spec does not require that individual BMCs in a
system have unique devices IDs, but it does require that the product id/device
id combination be unique.

This also removes a redundant check and cleans up error handling
when the sysfs registration fails.
Signed-off-by: Corey Minyard <minyard@acm.org>
Cc: Carol Hebert <cah@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>