fix misleading pr_err on poll timeout

If poll() times out, don't print a misleading errno, say that a timeout
occured.

Signed-off-by: Jiri Bohac <jbohac@suse.cz>
fix the check for supported timestamping modes

Fix the check for supported timestamping modes. The device needs
to support all the required modes, not just any subset of them.

Signed-off-by: Jiri Bohac <jbohac@suse.cz>