mpv: k0: use opengl again
mpv: k0: use opengl again

NixOS 17.03 comes with NVIDIA driver version 375.39, which fixes OpenGL issues
for the Quadro K1200 card on this machine (the driver in NixOS 16.09 resulted in
segfaults for all OpenGL apps).

listx/syscfg,listx/syscfg,listx/syscfg,listx/syscfg,listx/syscfg