IB/core: Bound check alternate path port number

IB/core: Bound check alternate path port number

commit 4cae8ff136782d77b108cb3a5ba53e60597ba3a6 upstream.

The alternate port number is used as an array index in the IB
security implementation, invalid values can result in a kernel panic.

Fixes: d291f1a65232 ("IB/core: Enforce PKey security on QPs")
Signed-off-by: Daniel Jurgens <danielj@mellanox.com>
Reviewed-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>