vfio/ccw: don't group contiguous pages on 2K IDAWs

The vfio_pin_pages() interface allows contiguous pages to be
pinned as a single request, which is great for the 4K pages
that are normally processed. Old IDA formats operate on 2K
chunks, which makes this logic more difficult.

Since these formats are rare, let's just invoke the page
pinning one-at-a-time, instead of trying to group them.
We can rework this code at a later date if needed.

Signed-off-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>