RDMA/ocrdma: Support user AH creation for RoCE-v2

This patch adds support to create RoCE-v2 compatible AH. It uses ahid
field to tell network-header-type to user space library. The library
has to decode network-header-type from ahid field.

Signed-off-by: Somnath Kotur <somnath.kotur@avagotech.com>
Signed-off-by: Devesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>