Bluetooth: hci_bcm: Fix -Wunused-const-variable warnings

If CONFIG_ACPI is not set, gcc warn this:

drivers/bluetooth/hci_bcm.c:831:39: warning:
 acpi_bcm_int_last_gpios defined but not used [-Wunused-const-variable=]
drivers/bluetooth/hci_bcm.c:838:39: warning:
 acpi_bcm_int_first_gpios defined but not used [-Wunused-const-variable=]

move them to #ifdef CONFIG_ACPI block.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>