iio: iio get channel and get event error checking
iio: iio get channel and get event error checking

Signed-off-by: Lay, Kuan Loon <835688da874a20a734cfb7f888d2ac8760d40914@intel.com>
Signed-off-by: Brendan Le Foll <3e0e8c4069934e8b47d99704927a85c66c0ceb33@intel.com>

arfoll/mraa,alext-mkrs/mraa,yongli3/mraa,anonymouse64/mraa,stefan-andritoiu/mraa,alext-mkrs/mraa,g-vidal/mraa,arfoll/mraa,stefan-andritoiu/mraa-gpio-chardev,ProfFan/mraa,spitfire88/mraa,intel-iot-devkit/mraa,intel-iot-devkit/mraa,Pillar1989/mraa,yongli3/mraa,petreeftime/mraa,alext-mkrs/mraa,petreeftime/mraa,petreeftime/mraa,KurtE/mraa,spitfire88/mraa,anonymouse64/mraa,g-vidal/mraa,anonymouse64/mraa,jontrulson/mraa,KurtE/mraa,ProfFan/mraa,ProfFan/mraa,arunlee77/mraa,sergev/mraa,stefan-andritoiu/mraa,andreivasiliu2211/mraa,alext-mkrs/mraa,ncrastanaren/mraa,intel-iot-devkit/mraa,sergev/mraa,yongli3/mraa,ncrastanaren/mraa,g-vidal/mraa,malikabhi05/mraa,Propanu/mraa,w4ilun/mraa,malikabhi05/mraa,Hbrinj/mraa,malikabhi05/mraa,jontrulson/mraa,whbruce/mraa,whbruce/mraa,arfoll/mraa,w4ilun/mraa,andreivasiliu2211/mraa,yongli3/mraa,intel-iot-devkit/mraa,sergev/mraa,Pillar1989/mraa,g-vidal/mraa,arfoll/mraa,stefan-andritoiu/mraa-gpio-chardev,malikabhi05/mraa,Pillar1989/mraa,g-vidal/mraa,stefan-andritoiu/mraa-gpio-chardev,Propanu/mraa,petreeftime/mraa,arunlee77/mraa,jontrulson/mraa,Jon-ICS/mraa,spitfire88/mraa,Jon-ICS/mraa,whbruce/mraa,w4ilun/mraa,ncrastanaren/mraa,intel-iot-devkit/mraa,ncrastanaren/mraa,whbruce/mraa,yongli3/mraa,malikabhi05/mraa,alext-mkrs/mraa,Jon-ICS/mraa,stefan-andritoiu/mraa,stefan-andritoiu/mraa-gpio-chardev,Hbrinj/mraa,arunlee77/mraa,w4ilun/mraa,Hbrinj/mraa,spitfire88/mraa,Propanu/mraa,sergev/mraa,stefan-andritoiu/mraa,sergev/mraa,stefan-andritoiu/mraa,stefan-andritoiu/mraa-gpio-chardev,KurtE/mraa,ncrastanaren/mraa,andreivasiliu2211/mraa,jontrulson/mraa,arunlee77/mraa,ProfFan/mraa,Propanu/mraa,Hbrinj/mraa,jontrulson/mraa,KurtE/mraa,Propanu/mraa,arfoll/mraa,KurtE/mraa,andreivasiliu2211/mraa