Add TAI clock offset to ptp instance examples.
currentUtcOffsetValid -> currentUtcOffsetValid=1
Add detail about removing currentUtcOffsetValid=1
to restore CLOCK_TAI offset to 0.
Story: 2010033
Task: 45434
Signed-off-by: Ron Stone <ronald.stone@windriver.com>
Change-Id: Ic7d0d5d03df0976584b645d8b0022c38ec694ed9