When executing the Full System simulation we have the option of enabling

dual mode where two hosts are directly linked via ethernet and simulated on

a single gem5 instance.
The FS mode has --ethernet-linkspeed and --ethernet-linkdelay options,

however these are not applied when using the --dual option.
This patch allows the two knobs to be applied to --dual mode as well.

Testing done on ARM version (AArch32) of FS
Tested with iperf and checked that with 1Gbps we get near 1Gbps

With 10Gbps, we get 6.61Gbps. (Probably due to low CPU frequency. It was running at default frequency)