net/mlx5e: Validate striding RQ before enabling XDP

Currently, the driver can silently fall back to legacy RQ after enabling
XDP, even if striding RQ was active before. It happens when PAGE_SIZE is
bigger than the maximum supported stride size. This commit changes this
behavior to more straightforward: if an operation (enabling XDP) doesn't
support the current parameters (striding RQ mode), it fails.

Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>