Add stack/include/hcidefs::hci_role helpers and aliases am: 6ca70a58 am:...

Add stack/include/hcidefs::hci_role helpers and aliases am: 6ca70a58 am: 4cea724e am: 3cdbde9c

Original change: https://android-review.googlesource.com/c/platform/system/bt/+/1629200

Change-Id: I3fb1b4c9bcdb2967a8256955c700433f2a099d20