net/mlx5: swap items/actions validations for E-Switch rules

net/mlx5: swap items/actions validations for E-Switch rules

The rule validation function for E-Switch checks item list first,
then action list is checked. This patch swaps the validation order,
now actions are checked first. This is preparation for validation
function update with VXLAN tunnel actions. VXLAN decapsulation
action requires to check the items in special way. We could do
this special check in the single item check pass if the action
flags were gathered before. This is the reason to swap the
item/actions checking loops.

Suggested-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
Acked-by: Yongseok Koh <yskoh@mellanox.com>