IB/mlx4: Fix RSS hash fields restrictions

Mistakenly the driver didn't allow RSS hash fields combinations which
involve both IPv4 and IPv6 protocols. This bug caused to failures for
user's use cases for RSS.

Consequently, this patch fixes this bug and allows any combination that
the HW can support.

Additionally, the patch fixes the driver to return an error in case the
user provides an unsupported mask for RSS hash fields.

Fixes: 3078f5f1

 ("IB/mlx4: Add support for RSS QP")
Signed-off-by: Guy Levi <guyle@mellanox.com>
Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>