net/mlx5e: Fix DCB_CAP_ATTR_DCBX capability for DCBNL getcap.

net/mlx5e: Fix DCB_CAP_ATTR_DCBX capability for DCBNL getcap.

[ Upstream commit 9e10bf1d349787f373484d835efe2dbb5f9c5614 ]

Current code doesn't report DCB_CAP_DCBX_HOST capability when query
through getcap. User space lldptool expects capability to have HOST mode
set when it wants to configure DCBX CEE mode. In absence of HOST mode
capability, lldptool fails to switch to CEE mode.

This fix returns DCB_CAP_DCBX_HOST capability when port's DCBX
controlled mode is under software control.

Fixes: 3a6a931dfb8e ("net/mlx5e: Support DCBX CEE API")
Signed-off-by: Huy Nguyen <huyn@mellanox.com>
Reviewed-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>