1. Replaced few commands with updated ones.
2. Updated the title from "SyncE and Introduction" to "SyncE Introduction".
3. Added a note in "Instance Specific Considerations" section.
4. Added and modifed few content in PTP Introduction and General Information sections.
(Added PHC to the abbreviation list).
Change-Id: I1d457c379869e264663a82625b1373384de16033
Signed-off-by: Dinesh Neelapu <dinesh.neelapu@windriver.com>