CVE-2026-68247 drm/i915/bios: range check LFP Data Block panel_type2

In the Linux kernel, the following vulnerability has been resolved: drm/i915/bios: range check LFP Data Block paneltype2 While the paneltype from LFP Data Block is range checked, paneltype2 is not. Add a few helpers for range checking, and use them to not only check paneltype2, but also improve...