staging: speakup: Use time_after_eq to compare jiffies in speakup_keypc.c

The following patch fixes the checkpatch.pl warning:
WARNING: Comparing jiffies is almost always wrong; prefer time_after,
time_before and friends

Signed-off-by: Esra Altintas <es.altintas@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>