Update to kernel headers v4.12.3.

Test: Built angler.
Change-Id: Icbcf4fac2334de8409b049ed7a3b4c24b4e98ce9
diff --git a/libc/kernel/uapi/drm/drm_mode.h b/libc/kernel/uapi/drm/drm_mode.h
index f15f3c6..9e7ee92 100644
--- a/libc/kernel/uapi/drm/drm_mode.h
+++ b/libc/kernel/uapi/drm/drm_mode.h
@@ -77,6 +77,8 @@
 #define DRM_MODE_DIRTY_OFF 0
 #define DRM_MODE_DIRTY_ON 1
 #define DRM_MODE_DIRTY_ANNOTATE 2
+#define DRM_MODE_LINK_STATUS_GOOD 0
+#define DRM_MODE_LINK_STATUS_BAD 1
 struct drm_mode_modeinfo {
   __u32 clock;
   __u16 hdisplay;