MFH: r466923

graphics/mesa-dri: always lower kernel version check

Sandybridge on FreeBSD 11.* is also affected:

$ glxgears
[intel_init_bufmgr: 1685] Kernel 3.9 required.
libGL error: failed to create dri screen
libGL error: failed to load driver: i965
5373 frames in 5.0 seconds = 1074.496 FPS

Reported by: Kevin Oberman
PR: 225035 225415
Approved by: ports-secteam blanket