net/sched: act_pedit: remove extra check for key type

The netlink parsing already validates the key 'htype'.
Remove the datapath check as it's redundant.

Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>