Bluetooth: Avoid using GFP_ATOMIC where not necessary

The various pieces of data cached in the hci_dev structure do not need
to be allocated using GFP_ATOMIC since they are never added from
interrupt context. This patch updates these allocations to use
GFP_KERNEL instead.

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