rapidio/mport_cdev: fix uapi type definitions

Fix problems in uapi definitions reported by Gabriel Laskar: (see
https://lkml.org/lkml/2016/4/5/205

 for details)

 - move public header file rio_mport_cdev.h to include/uapi/linux directory
 - change types in data structures passed as IOCTL parameters
 - improve parameter checking in some IOCTL service routines

Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
Reported-by: Gabriel Laskar <gabriel@lse.epita.fr>
Tested-by: Barry Wood <barry.wood@idt.com>
Cc: Gabriel Laskar <gabriel@lse.epita.fr>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: Andre van Herk <andre.van.herk@prodrive-technologies.com>
Cc: Barry Wood <barry.wood@idt.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>