rapidio: integrate rio_switch into rio_dev

Convert RIO switches device structures (rio_dev + rio_switch) into a
single allocation unit.

This change is based on the fact that RIO switches are using common RIO
device objects anyway.  Allocating RIO switch objects as RIO devices with
added space for switch information simplifies handling of RIO switch
devices.

Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Cc: Thomas Moll <thomas.moll@sysgo.com>
Cc: Micha Nelissen <micha@neli.hopto.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>