opengl: fix xyz12 fragment shader
Commits bf4f21b5 and cb16845b moved transformations from the renderer to the (sampler) fragment shader.
But the transformations were applied only on the "main" fragment shader. Also apply them on the specific fragment shader generated for XYZ12 chroma.
This fixes this error on XYZ12 videos:
vlc: ../../modules/video_output/opengl/renderer.c:360: opengl_link_program: Assertion `renderer->uloc.TransformMatrix != -1' failed.
Aborted
Edited by Romain Vimont