f_flower: don't set TCA_FLOWER_KEY_ETH_TYPE for "protocol all"

f_flower: don't set TCA_FLOWER_KEY_ETH_TYPE for "protocol all"

v2 - update to address changes in 00697ca19ae3e1118f2af82c3b41ac4335fe918b.

When using the tc flower filter, rules marked with "protocol all" do not
actually match all packets.  This is due to a bug in f_flower.c that passes
in ETH_P_ALL in the TCA_FLOWER_KEY_ETH_TYPE attribute when adding a rule.
Fix this by omitting TCA_FLOWER_KEY_ETH_TYPE if the protocol is set to
ETH_P_ALL.

Fixes: 488b41d020fb ("tc: flower no need to specify the ethertype")
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Benjamin LaHaise <benjamin.lahaise@netronome.com>
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
Reviewed-by: Roi Dayan <roid@mellanox.com>