Claim device lock to safely enumerate hci connection list and bump hci connection proxy device ref count simultaneously. Also it prevents kernel crash due to null pointer conn->hdev in deleting conn entry from sysfs. CRs-Fixed: 446403 Change-Id: I5ec4283d359f95e47711dff171d0619b15263349 Signed-off-by: Sumit Bajpai <sbajpai@codeaurora.org> Signed-off-by: Mallikarjuna GB <gbmalli@codeaurora.org>