Hcidoc: Support multiple concurrent connections with the same address

Devices which uses the same address for BREDR and LE connections will
mess up with the internal processing of hcidoc because it assumed
only one connection at any given time per address.

Bug: 375370824
Test: m -j
Test: manually with pixel buds
Flag: EXEMPT, floss only change

Change-Id: I7e4d3ed24d15b74da70e44a480c67180b4233162