net/mlx5e: Don't cache tunnel offloads capability

When mlx5e attaches again after device health recovery, the device
capabilities might have changed by the eswitch manager.

For example in one flow when ECPF changes the eswitch mode between
legacy and switchdev, it updates the flow table tunnel capability.

The cached value is only used in one place, so just check the capability
there instead.

Fixes: 5bef709d ("net/mlx5: Enable host PF HCA after eswitch is initialized")
Signed-off-by: Parav Pandit <parav@nvidia.com>
Signed-off-by: Daniel Jurgens <danielj@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>