block: jiffies fixes

Use HZ-independent calculation of milliseconds.
Add jiffies.h where it was missing since functions or macros
from it are used.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --cc block/blk-settings.c
Simple merge

diff --cc block/bsg.c
Simple merge

diff --cc block/cfq-iosched.c
Simple merge