[BB][RP] Scan FRU from all address on a bus

The current assumption is each bus would only have one address.However
this is not true anymore with RayadoPeaScan.

On RP, there are 2 addresses under one bus, but the FRU is only on one
of the address. This commit scan all the addresses on a bus, and return
as when FRU is read from any address.

Tested:
on BB/ZB, nothing change.
On BB+RP, see the port bifurcated properly.
https://paste.googleplex.com/4526384594681856

Fusion-Link:
BB: https://fusion2.corp.google.com/016469dd-4202-4d68-8d6f-d9d6cfc64737
ZB: https://fusion2.corp.google.com/9241ae2e-c382-4065-a6fb-cd2c89352565

Google-Bug-Id: 475686116
Change-Id: Ib9486bd8b66e37dfdb7a7bbeb53bd95691b50476
Signed-off-by: Tao Ke <taok@google.com>