We found that monitor mode of mdadm does not work on RAID0, and it is
not a bug, expected behavior according to RHEL developer.
Therefore, we should stop enabling mdmonitor when RAID0 is specified.
Fixes#9540
----
This reverts 0d8f932 and introduce correct fix.
Closes#9970
* github.com:scylladb/scylla:
scylla_raid_setup: use mdmonitor only when RAID level > 0
Revert "scylla_raid_setup: workaround for mdmonitor.service issue on CentOS8"
(cherry picked from commit df22396a34)
50aad1c668