CVE-2026-72313 drm/fb-helper: Only consider active CRTCs for vblank sync

In the Linux kernel, the following vulnerability has been resolved: drm/fb-helper: Only consider active CRTCs for vblank sync Only synchronize fbdev output to the vblank of an active CRTC. Go over the list of CRTCs and pick the first that matches. Fixes warnings as the one shown below 77.201354...