video_core: Move OpenGL specific utils to its renderer

src/video_core/CMakeLists.txt

@@ -51,6 +51,8 @@ add_library(video_core STATIC
     renderer_opengl/maxwell_to_gl.h
     renderer_opengl/renderer_opengl.cpp
     renderer_opengl/renderer_opengl.h
+    renderer_opengl/utils.cpp
+    renderer_opengl/utils.h
     textures/astc.cpp
     textures/astc.h
     textures/decoders.cpp