net/mlx5e: Do early return when setup vports dests for slow path flow

Adding flow flag cases in setup vport dests before the slow path
case is incorrect as the slow path should take precedence.
Current code doesn't show this importance so make the slow path
case return early and separate from the other cases and remove
the redundant comparison of it in the sample case.

Signed-off-by: Roi Dayan <roid@nvidia.com>
Reviewed-by: Chris Mi <cmi@nvidia.com>
Reviewed-by: Oz Shlomo <ozsh@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>