The lens profile is normally applied to your JPG images in camera so Lightroom doesn't apply them to JPG images.
With this lens I doubt that your camera will apply any lens correction. I suggest you use the Adobe Lens Profile Creator 1.0.4 and take some JPGs of the Adobe Camera Calibration Chart. With the JPG in Lightroom make your own manual lens correction adjustments then save the settings as a preset. You can then apply this preset to all your future JPGs.
Lens Profile for Rokinon Samyang 14mm 2.8
Markus Keinath - Samyang 14 mm / 2.8 IF ED MC Aspherical Test