Include log filtering in openshift ptp docs

Need to update docs to include log filtering

In 4.12 and later releases.

In order to avoid filling up linuxptp-daemon logs with master offset from ptp4l, introduced a new field in ptp config filter out and not log master offset to stdout.

example(use same prodecure as for configuring fifo):

apiVersion: ptp.openshift.io/v1
kind: PtpConfig
metadata:
  name: <ptp_config_name>
  namespace: openshift-ptp
...
spec:
  profile:
  - name: "profile1"
...
    ptpSettings:
      logReduce: "true"