rapidio/tsi721: add option to configure direct mapping of IB window

Add an option to configure mapping of Inbound Window without RIO-to-PCIe
address translation.

If a local memory buffer is not properly aligned to meet HW requirements
for RapidIO address mapping with address translation, caller can request
an inbound window with matching RapidIO address assigned to it.  This
implementation selects RapidIO base address and size for inbound window
that are capable to accommodate the local memory buffer.

Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: Andre van Herk <andre.van.herk@prodrive-technologies.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>