net/mlx5e: Properly block HW GRO when XDP is enabled

HW GRO is incompatible and mutually exclusive with XDP and XSK. However,
the needed checks are only made when enabling XDP. If HW GRO is enabled
when XDP is already active, the command will succeed, and XDP will be
skipped in the data path, although still enabled.

This commit fixes the bug by checking the XDP and XSK status in
mlx5e_fix_features and disabling HW GRO if XDP is enabled.

Fixes: 83439f3c ("net/mlx5e: Add HW-GRO offload")
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>