modesetting: Do not fail if glamor fails.

If glamor initialization fails, we can still use the good old fb code.

Downgrade the glamor initialization error as a warning and move on.

Signed-off-by: Olivier Fourdan <>
Closes: xorg/xserver#99
4 jobs for modesetting-no-glamor in 5 minutes and 5 seconds (queued for 1 second)