rapidio: add enabling SRIO port RX and TX

Add the functionality to enable Input receiver and Output transmitter of
every port, to allow non-maintenance traffic.

Signed-off-by: Thomas Moll <thomas.moll@sysgo.com>
Signed-off-by: Alexandre Bounine <abounine@tundra.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>