Bluetooth: Merge hdev->dbg_flags fields into hdev->dev_flags

With the extension of hdev->dev_flags utilizing a bitmap now, the space
is no longer restricted. Merge the hdev->dbg_flags into hdev->dev_flags
to save space on 64-bit architectures. On 32-bit architectures no size
reduction happens.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>