net/sched: cls_flower: Try to offload only if skip_hw flag isn't set

Check skip_hw flag isn't set before calling
fl_hw_{replace/destroy}_filter and fl_hw_update_stats functions.

Replace the call to tc_should_offload with tc_can_offload.
tc_can_offload only checks if the device supports offloading, the check for
skip_hw flag is done earlier in the flow.

Signed-off-by: Hadar Hen Zion <hadarh@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>