net/mlx5e: Remove assignment of inline_hdr.sz on XDP TX

When MPWQE is disabled, mlx5e_open_xdpsq prefills the common fields of
WQEs in the XDP SQ to save time when sending packets. One of such fields
is eseg->inline_hdr.sz, which can be either 0 or MLX5E_XDP_MIN_INLINE,
depending on the inline mode of the SQ.

The inline mode can't change during the lifetime of the SQ, so setting
this field again in mlx5e_xmit_xdp_frame is redundant. Moreover, the
xmit function only sets it to MLX5E_XDP_MIN_INLINE, but not to 0 in the
other case.

This commit removes the redundant assignment in mlx5e_xmit_xdp_frame.

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