net/mlx5e: Fix usage of DMA sync API

DMA sync functions should use the same direction that was used by DMA
mapping. Use DMA_BIDIRECTIONAL for XDP_TX from regular RQ, which reuses
the same mapping that was used for RX, and DMA_TO_DEVICE for XDP_TX from
XSK RQ and XDP_REDIRECT, which establish a new mapping in this
direction. On the RX side, use the same direction that was used when
setting up the mapping (DMA_BIDIRECTIONAL for XDP, DMA_FROM_DEVICE
otherwise).

Also don't skip sync for device when establishing a DMA_FROM_DEVICE
mapping for RX, as some architectures (ARM) may require invalidating
caches before the device can use the mapping. It doesn't break the
bugfix made in
commit 0b7cfa40 ("net/mlx5e: Fix page DMA map/unmap attributes"),
since the bug happened on unmap.

Fixes: 0b7cfa40 ("net/mlx5e: Fix page DMA map/unmap attributes")
Fixes: b5503b99

 ("net/mlx5e: XDP TX forwarding support")
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Gal Pressman <gal@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>