hw/xfree86: Propagate physical dimensions from DRM connector

Physical dimmension of display can be obtained not just by configuration or
DDC, but also directly from kernel via drmModeGetConnector(). Until now
xserver silently discarded these values even when no configuration nor EDID
were present and fallbacked to default DPI.
8 jobs for drmdimensionsfix in 8 minutes and 1 second (queued for 3 seconds)
Status Job ID Name Coverage
  Docker Image
passed #2738669
debian-testing

00:00:56

 
  Build And Test
passed #2743064
autotools

00:07:04

passed #2743065
meson

00:02:27

passed #2743066
meson-noglamor

00:02:24

failed #2738671
autotools

00:02:35

failed #2738673
meson

00:02:35

failed #2738675
meson-noglamor

00:02:35

failed #2739022
meson-noglamor

00:01:08