This pointer really is a struct ib_device, not a struct device, so name
it properly to help prevent confusion.

This makes the followon patch in this series much smaller and easier to
understand as well.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Roland Dreier <rolandd@cisco.com>
Cc: Hal Rosenstock <hal.rosenstock@gmail.com>
Acked-by: NSean Hefty <sean.hefty@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>