Bluetooth: btusb: off by one in rtl8723b_parse_firmware()

The ">" should be ">=" so that we don't read past the end of the array.

Fixes: 9d9a113e3695 ('Bluetooth: btusb: Add Realtek 8723A/8723B/8761A/8821A support')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Daniel Drake <drake@endlessm.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>