Bluetooth: GAP: Avoid adding device to cached device list

Change will ensure that devices will not be added to the cached
device list if profile connection state is STATE_DISCONNECTED
or STATE_DISCONNECTING. Otherwise, devices will be added to cached
list and while inquring device will not be listed in available
device list.

CRs-Fixed: 586975
Change-Id: I60bc01c0f2cb5ea87f3c633bcec2f04c90939d67