selftests: ocelot: tc_flower_chains: use conventional interface names

This is a robotic rename as follows:

eth0 -> swp1
eth1 -> swp2
eth2 -> h2
eth3 -> h1

This brings the selftest more in line with the other forwarding
selftests, where h1 is connected to swp1, and h2 to swp2.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>