iio.hpp: Added an empty destructor to get rid of a warning
iio.hpp: Added an empty destructor to get rid of a warning

Signed-off-by: Nicola Lunghi <4828aa2f171daefde723b3eaeea1dd38094b115f@emutex.com>
Signed-off-by: Brendan Le Foll <3e0e8c4069934e8b47d99704927a85c66c0ceb33@intel.com>

stefan-andritoiu/mraa-gpio-chardev,malikabhi05/mraa,yongli3/mraa,alext-mkrs/mraa,spitfire88/mraa,arfoll/mraa,stefan-andritoiu/mraa-gpio-chardev,Propanu/mraa,ncrastanaren/mraa,arfoll/mraa,g-vidal/mraa,yongli3/mraa,Jon-ICS/mraa,Propanu/mraa,whbruce/mraa,jontrulson/mraa,sergev/mraa,jontrulson/mraa,sergev/mraa,intel-iot-devkit/mraa,arunlee77/mraa,jontrulson/mraa,malikabhi05/mraa,g-vidal/mraa,g-vidal/mraa,arunlee77/mraa,alext-mkrs/mraa,sergev/mraa,g-vidal/mraa,whbruce/mraa,arfoll/mraa,stefan-andritoiu/mraa,g-vidal/mraa,intel-iot-devkit/mraa,w4ilun/mraa,ncrastanaren/mraa,Jon-ICS/mraa,ncrastanaren/mraa,arfoll/mraa,whbruce/mraa,KurtE/mraa,Jon-ICS/mraa,Propanu/mraa,stefan-andritoiu/mraa-gpio-chardev,KurtE/mraa,w4ilun/mraa,spitfire88/mraa,yongli3/mraa,sergev/mraa,stefan-andritoiu/mraa,arunlee77/mraa,alext-mkrs/mraa,malikabhi05/mraa,stefan-andritoiu/mraa,alext-mkrs/mraa,KurtE/mraa,w4ilun/mraa,Propanu/mraa,w4ilun/mraa,malikabhi05/mraa,KurtE/mraa,spitfire88/mraa,sergev/mraa,intel-iot-devkit/mraa,jontrulson/mraa,arunlee77/mraa,stefan-andritoiu/mraa-gpio-chardev,stefan-andritoiu/mraa,KurtE/mraa,intel-iot-devkit/mraa,malikabhi05/mraa,yongli3/mraa,spitfire88/mraa,intel-iot-devkit/mraa,ncrastanaren/mraa,arfoll/mraa,stefan-andritoiu/mraa,jontrulson/mraa,whbruce/mraa,yongli3/mraa,alext-mkrs/mraa,stefan-andritoiu/mraa-gpio-chardev,ncrastanaren/mraa,Propanu/mraa