intel_edison_fab: enable support for vanilla kernels >= 4 for serial
intel_edison_fab: enable support for vanilla kernels >= 4 for serial

This disables changing pinmux as this is envisioned to be done through acpi
provided by u-boot

Signed-off-by: Ferry Toth <b7ff6f7d33f1b320413095ad62cad5fa92c49512@exalondelft.nl>
Signed-off-by: Brendan Le Foll <3e0e8c4069934e8b47d99704927a85c66c0ceb33@intel.com>

sergev/mraa,intel-iot-devkit/mraa,arfoll/mraa,yongli3/mraa,stefan-andritoiu/mraa,ncrastanaren/mraa,intel-iot-devkit/mraa,KurtE/mraa,yongli3/mraa,alext-mkrs/mraa,stefan-andritoiu/mraa,ncrastanaren/mraa,Propanu/mraa,ncrastanaren/mraa,stefan-andritoiu/mraa,alext-mkrs/mraa,ncrastanaren/mraa,arfoll/mraa,intel-iot-devkit/mraa,g-vidal/mraa,intel-iot-devkit/mraa,malikabhi05/mraa,intel-iot-devkit/mraa,malikabhi05/mraa,yongli3/mraa,KurtE/mraa,sergev/mraa,Propanu/mraa,malikabhi05/mraa,arfoll/mraa,alext-mkrs/mraa,KurtE/mraa,alext-mkrs/mraa,sergev/mraa,KurtE/mraa,arfoll/mraa,arfoll/mraa,KurtE/mraa,g-vidal/mraa,yongli3/mraa,stefan-andritoiu/mraa,yongli3/mraa,g-vidal/mraa,alext-mkrs/mraa,ncrastanaren/mraa,g-vidal/mraa,malikabhi05/mraa,Propanu/mraa,sergev/mraa,malikabhi05/mraa,g-vidal/mraa,Propanu/mraa,sergev/mraa,Propanu/mraa,stefan-andritoiu/mraa