Bluetooth: hci_mrvl: use maybe_unused macro for device tree ids

Use the maybe_unused macro for the device tree ids instead of #ifdef
CONFIG_OF. This makes it easier to add support for new devices.

Signed-off-by: Stefan Eichenberger <stefan.eichenberger@toradex.com>
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>