The uart_proto open() callback is not called in atomic context so we can safely
sleep here. The caller hci_uart_set_proto() in hci_ldisc.c is an ioctl-handler
and therefore can sleep.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com> Acked-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>