drm/amd/display: fix missing .is_two_pixels_per_container

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: fix missing .is_two_pixels_per_container Starting from 6.11, AMDGPU driver, while being loaded with amdgpu.dc=1, due to lack of .is_two_pixels_per_container function in dce60_tg_funcs, causes a NULL pointer dereference on PCs with old GPUs, such as R9 280X. So this fix adds missing .is_two_pixels_per_container to dce60_tg_funcs. (cherry picked from commit bd4b125eb949785c6f8a53b0494e32795421209d)