osd: Change scrub cost in case of mClock scheduler

osd: Change scrub cost in case of mClock scheduler

With osd_op_queue as WPQ, high costs were assigned to scrub in order to throttle it effectively.
In the case of mClock scheduler, mClock parameters are used to do the throttling and the cost should represent a realistic value.

Fixes: https://tracker.ceph.com/issues/61313
Signed-off-by: Aishwarya Mathuria <amathuri@redhat.com>
(cherry picked from commit 43544d296c5fc14aaf638ddf21de9ea9d99f6059)

src/osd/OSD.cc: We are using osd_scrub_chunk_max in the scrub cost calculation here.