IB/core: Add inline function to validate port

commit 24dc831b77eca9361cf835be59fa69ea0e471afc upstream.

Signed-off-by: Yuval Shaia <yuval.shaia@oracle.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
[bwh: Backported to 3.2:
 - Drop inapplicable changes
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --cc drivers/infiniband/core/cache.c
Simple merge

diff --cc drivers/infiniband/core/device.c
Simple merge

diff --cc include/rdma/ib_verbs.h
Simple merge