RDMA/mana_ib: query device capabilities

With RDMA device registered, use it to query on hardware capabilities and
cache this information for future query requests to the driver.

Signed-off-by: Long Li <longli@microsoft.com>
Link: https://lore.kernel.org/r/1702692255-23640-3-git-send-email-longli@linuxonhyperv.com


Signed-off-by: Leon Romanovsky <leon@kernel.org>