dm bufio: fix time comparison to use time_after_eq()

To be future-proof and for better readability the time comparison
is modified to use time_after_eq() instead of plain, error-prone math.

Signed-off-by: Asaf Vertz <asaf.vertz@tandemg.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
1 file changed