intel_edison_fab_c.c: don't undo muxing if we don't own the pin
intel_edison_fab_c.c: don't undo muxing if we don't own the pin

Signed-off-by: Brendan Le Foll <3e0e8c4069934e8b47d99704927a85c66c0ceb33@intel.com>

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