modesetting: Reduce "glamor initialization failed" message to X_INFO

This might be an error or not, for example refusing to work on llvmpipe
is normal and expected. glamor_egl_init() will print X_ERROR messages if
appropriate, so we don't need to here.

Reviewed-by: Michel Dänzer <mdaenzer@redhat.com>
3 jobs for glamor-init-message-hush in 8 minutes and 36 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Docker Image
passed #679429
debian-testing

00:00:36

 
  Build And Test
passed #679430
autotools-build-and-test

00:06:27

passed #679431
meson-build-and-test

00:01:33